| addendum | Latin | an item added at the end of a document | The publisher issued an addendum clarifying the data sources. |
| ad hoc | Latin | arranged for a specific purpose; improvised | An ad hoc panel reviewed the complaint. |
| ad hominem | Latin | directed at the person rather than the argument | That ad hominem attack adds nothing to the debate. |
| ad infinitum | Latin | endlessly; without limit | The loop could repeat ad infinitum without a stop condition. |
| ad libitum (ad lib) | Latin | at one’s pleasure; improvised | She added a witty ad lib during the performance. |
| ad nauseam | Latin | to a sickening or excessive degree | We’ve discussed that policy ad nauseam. |
| ad valorem | Latin | in proportion to value (esp. tax/duty) | The import faces an ad valorem duty of 8%. |
| agent provocateur | French | person who incites others to commit illegal acts to entrap them | The rally was disrupted by an agent provocateur. |
| aide-de-camp | French | military officer acting as a senior’s assistant | The general’s aide-de-camp coordinated logistics. |
| aide-mémoire | French | reminder; memorandum | She kept an aide-mémoire of key dates. |
| à la carte | French | items priced/ordered separately | We skipped the set menu and went à la carte. |
| à la mode | French | in fashion; (US) served with ice cream | He ordered apple pie à la mode. |
| alfresco | Italian | in the open air; outdoors | Let’s have an alfresco lunch on the terrace. |
| alma mater | Latin | one’s former school or university | He donates annually to his alma mater. |
| alter ego | Latin | a second self; intimate trusted friend | The narrator is the author’s alter ego. |
| amour propre | French | self-respect; self-regard | His amour propre wouldn’t allow another slight. |
| Anno Domini (AD) | Latin | “in the year of the Lord”; dating label | The cathedral was completed in AD 1145. |
| ante meridiem (a.m.) | Latin | before noon | The train arrives at 9:12 a.m. |
| a posteriori | Latin | from observed facts; empirical | That’s an a posteriori conclusion drawn from the survey. |
| a priori | Latin | from theory; independent of experience | A priori, the result should hold for all n. |
| à propos | French | with reference to; to the point | À propos of budgets, we need to cut travel. |
| art nouveau | French | decorative art/architecture style (c. 1890–1910) | The station’s art nouveau façade was restored. |
| au fait | French | well informed; knowledgeable | She’s au fait with EU privacy rules. |
| au pair | French | live-in helper from abroad | They hired an au pair for the summer. |
| beau monde | French | fashionable society | The gala drew the city’s beau monde. |
| bête noire | French | something strongly disliked | Paperwork is my bête noire. |
| bona fide | Latin | genuine; in good faith | He’s a bona fide expert on coral reefs. |
| bon appétit | French | enjoy your meal | Dinner is served—bon appétit! |
| bon voyage | French | have a good trip | Bon voyage—send photos from Sicily! |
| carte blanche | French | complete freedom to act | The director got carte blanche on casting. |
| chargé d’affaires | French | diplomat heading an embassy in the ambassador’s absence | The chargé d’affaires met the delegation. |
| chef-d’œuvre | French | masterpiece | Critics called the film a chef-d’œuvre. |
| coup de grâce | French | the finishing blow or event | The recall was the coup de grâce for sales. |
| coup d’état | French | sudden overthrow of a government | The coup d’état lasted only 48 hours. |
| crème de la crème | French | the very best | She recruits from the crème de la crème of grads. |
| cul-de-sac | French | road closed at one end; dead end | Negotiations reached a cul-de-sac. |
| de facto | Latin | in fact; in practice though not by law | He’s the de facto team lead. |
| de jure | Latin | by law; rightful | They’re de jure equals but not de facto. |
| de rigueur | French | required by etiquette or fashion | Black tie is de rigueur at this gala. |
| en bloc | French | all together; as a whole | The board rejected the terms en bloc. |
| en masse | French | in a group; all together | Fans arrived en masse at dawn. |
| esprit de corps | French | group spirit and loyalty | Training built strong esprit de corps. |
| ex officio | Latin | by virtue of one’s office | The dean serves ex officio on the board. |
| ex parte | Latin | for one side only (legal) | The judge issued an ex parte order. |
| ex tempore | Latin | without preparation; impromptu | She offered an ex tempore reply. |
| fait accompli | French | thing already done; irreversible | By sunrise, the merger was a fait accompli. |
| faux pas | French | social blunder | Forgetting her name was a faux pas. |
| femme fatale | French | seductive, dangerous woman | The film’s femme fatale steals every scene. |
| Homo sapiens | Latin | human beings (species name) | Homo sapiens evolved complex language. |
| in situ | Latin | in the original or proper place | Artifacts were preserved in situ. |
| inter alia | Latin | among other things | The report cites, inter alia, climate risks. |
| in toto | Latin | as a whole; entirely | They rejected the proposal in toto. |
| ipso facto | Latin | by that very fact | Being loud isn’t ipso facto rude. |
| laissez-faire | French | policy of non-interference | He favors a laissez-faire approach to markets. |
| lapis lazuli | Latin (via Persian) | a bright blue semi-precious stone | The pendant was set with lapis lazuli. |
| lingua franca | Italian/Med. | common language between speakers | English is the lingua franca of aviation. |
| locus standi | Latin | right to bring action before a court | The NGO lacked locus standi in this case. |
| modus operandi | Latin | characteristic method of working | The pattern fits the suspect’s modus operandi. |
| modus vivendi | Latin | workable arrangement between parties | They found a modus vivendi on schedules. |
| non sequitur | Latin | conclusion that doesn’t follow | That’s a non sequitur—try again. |
| nota bene (N.B.) | Latin | note well; pay special attention | N.B.: Submissions close Friday. |
| nouveau riche | French | newly rich (often pejorative) | The resort teemed with the nouveau riche. |
| nouvelle cuisine | French | modern light French cooking | The bistro serves nouvelle cuisine classics. |
| par excellence | French | quintessential; pre-eminently | She’s a teacher par excellence. |
| persona non grata | Latin | unwelcome person (esp. diplomatic) | He was declared persona non grata. |
| post mortem | Latin | after death; analysis after an event | We held a post mortem on the outage. |
| prima facie | Latin | at first sight; on first impression | There’s a prima facie case of negligence. |
| pro bono (publico) | Latin | for the public good; without charge | The firm took the case pro bono. |
| pro forma | Latin | as a formality; standard template | We issued a pro forma invoice. |
| pro rata | Latin | in proportion | Vacation days accrue pro rata. |
| quid pro quo | Latin | a favor/item given in exchange | It was a quid pro quo: tickets for feedback. |
| raison d’être | French | reason for being; justification | Education is the charity’s raison d’être. |
| sine die | Latin | without a set date; indefinitely | The hearing was adjourned sine die. |
| sine qua non | Latin | indispensable condition | Trust is the sine qua non of teamwork. |
| status quo | Latin | existing state of affairs | They opted to preserve the status quo. |
| sub judice | Latin | under judicial consideration; not for public comment | We can’t discuss it—it’s sub judice. |
| subpoena | Latin | writ ordering someone to appear or produce evidence | She received a subpoena to testify Monday. |
| table d’hôte | French | fixed-price set meal | The inn offers a rustic table d’hôte nightly. |
| tête-à-tête | French | private conversation between two | They had a brief tête-à-tête after the meeting. |
| tour de force | French | impressive display of skill | Her solo was a tour de force. |
| ultra vires | Latin | beyond one’s legal power/authority | The action was ruled ultra vires. |
| vice versa | Latin | the other way around | She mentors him and vice versa. |
| vis-à-vis | French (via Latin) | in relation to; compared with; face-to-face | What’s our plan vis-à-vis competitors? |
