From Real Simple Magazine:

Words You Might Read
Ad hominem (add HAH-min-em); Latin
Definition: Appealing to prejudices and emotions rather than reason;
attacking an opponent's character rather than her arguments.
Usage: It was clear Susan would lose her bid for the condo board when she
responded to her opponent with the ad hominem attack "I'm sure your pet rat —
or is it a Yorkie? — brings you much joy."
Worth Noting: Ad hominem is often followed by the word attack.

Ad infinitum (add inn-finn-EYE-tuhm); Latin
Definition: To infinity.
Usage: Though the kids in the backseat sang "Ninety-nine Bottles of Beer on
the Wall" for a mere two hours, it seemed to go on ad infinitum.

Après (AH-pray); French
Definition: After.
Usage: She loves the après-ski ritual — wearing a colorful sweater and
drinking hot toddies — even though she never skis.

Bête Noire (bet NWAHR); French
Definition: A dreaded or detested person or thing.
Usage: At large family gatherings, my sister-in-law is my bête noire,
lurking in the kitchen and criticizing my cooking skills.

E.G. (abbreviation for exempli gratia); Latin
Definition: For example.
Usage: While arachnophobia is fairly common, there are far more unusual
fears, e.g., arachibutyrophobia — the fear of peanut butter sticking to the roof
of one's mouth.

I.E. (abbreviation for id est); Latin
Definition: In other words.
Usage: Even today he suffers from coulrophobia — i.e., a morbid fear of
clowns.
Worth Noting: These two abbreviations are often incorrectly reversed.
Remember that e.g. is used to illustrate a point, while i.e. is used to clarify it.

Enfant Terrible (on-fon teh-REE-bleh); French
Definition: A difficult child; an unconventional or outspoken person whose
behavior dismays or embarrasses others.
Usage: She's definitely the staff enfant terrible, with her dramatics at the
weekly staff meetings, her loudmouthed phone conversations, and the rest of
us cringing in her wake.

Quid Pro Quo (kwid proh KWOH); Latin
Definition: An equal exchange.
Usage: Quid pro quo, kiddo: You clean your room and I'll let you have an
extra hour on the GameCube.

Sturm und Drang (SHTOORM oont DRONG); German
Definition: Turmoil, upheaval.
Usage: The memo declaring an end to casual Fridays caused no end of Sturm
und Drang among my jeans-loving officemates.
Ad Nauseam (add NAWZ-ee-am); Latin
Definition: To a sickening degree.
Usage: My neighbor fretted about her garden ad nauseam, but I could not care
less about her bad bulb season.

Chez (shay); French
Definition: At the home of; at or by. Often used with the French word nous
(we), meaning "at our home."
Usage: You're invited to a party chez nous.
Worth Noting: Don't say "You're invited to a party at chez nous."

Faux Pas (foe pah); French
Definition: A social blunder.
Usage: Criticizing the boss's daughter was just her first faux pas on the
new job.

Mensch (mentsh); Yiddish
Definition: A person of honor and integrity; a decent, upright person.
Usage: His grandfather always used to tell him, "Comb your hair, straighten
your tie, look people in the eye, and be a mensch."
Worth Noting: The word mensch may sound less complimentary than it is. Many
people mistake it for a put-down.

Shlemiel (shleh-MEEL); Yiddish
Shlimazel (shlih-MAH-zull); Yiddish
Definition: The schlemiel is a fool; the schlimazel is an unlucky person.
The schlemiel is forever messing things up, while the schlimazel is always on
the wrong end of the schlemiel's foul-ups.
Usage: That schlemiel can get lost driving around the block. Take it from
the schlimazel who gets a ride with him every day.
Worth Noting: Both words entered common American conversation with the theme
song to TV's Laverne and Shirley, which kicked off with "Shlemiel,
shlimazel, Hasenpfeffer Incorporated...."

Schlep (shlep); Yiddish
Definition: To drag, carry with difficulty, travel slowly or awkwardly.
Usage: The elevator was on the fritz, so we had to schlep our suitcases all
the way up.

Shmooze (shmooz); Yiddish
Definition: To talk casually, chat, network.
Usage: In Hollywood it's all about whom you know — and shmoozing really pays
off.

Vis-à-Vis (VEEZ-ah-VEE); French
Definition: Face-to-face with; compared with; in regard to.
Usage: My thoughts vis-à-vis the new highway are mixed: It will be good for
business but will also increase pollution and noise.
Worth Noting: Vis-à-vis is most often misused as a way to describe an
agreement between two people.
Bon Mot (bouh MOE); French
Definition: A clever remark or witticism.
Usage: He's a delightful party guest — well-dressed, polite, and always
ready with a bon mot.
Worth Noting: Say "bon" with a nasalized French sound; the N is not actually
pronounced.

Chacun à Son Goût (sha-KUHN ahh sauh GOOO); French
Definition: Each to his or her own taste.
Usage: I'd never install an aboveground pool, but chacun à son goût.

Eminence Grise (AY-mee-nahns GREEZ); French
Definition: Someone who wields considerable power secretly or unofficially,
a "power behind the throne."
Usage: Most of us know that Cindy's 10-year-old is the éminence grise of the
block association.

Je Ne Sais Pas (jehn say pah); French
Definition: I don't know.
Usage: What day does Saint Valentine's fall on this year? Je ne sais pas.
Worth Noting: Often confused with je ne sais quoi, which means something
that can't be described.

Joie de Vivre (jwa dih VEE-vruh); French
Definition: A hearty enjoyment of life. Literally, "joy of living."
Usage: Granny has real joie de vivre. She drives a convertible, listens to
rock and roll, and still surfs waves with the best of them.

Ne Plus Ultra (neh ploos UL-trah); Latin
Definition: The ultimate; the highest point of achievement or excellence;
the most profound degree of a quality or state. Literally, "no more beyond."
Usage: Heirloom roses are the ne plus ultra of garden flowers, but how are
your mums doing?

Persona non Grata (purr-SOH-nuh nahn GRAH-tuh); Latin
Definition: Unacceptable or unwelcome.
Usage: Billy has been persona non grata around our house ever since he hit a
baseball through our sliding-glass door.

Pièce de Résistance (pee-ESS dih ray-zees-TAHNSS); French
Definition: The prized item in a collection; a cook's signature dish.
Usage: Mary's scrumptious chocolate cake is always the pièce de résistance
of the neighborhood potluck.

Raison d'Etre (RAY-zohn DEH-truh); French
Definition: Reason for being.
Usage: My dog Bruno's raison d'être is simple: Hound the cat as much as
possible.

Schadenfreude (shah-dunn-FROY-duh); German
Definition: Pleasure felt at another person's misfortune.
Usage: I know it's schadenfreude, but I was inwardly thrilled when my evil
officemate gained an extra 20 pounds.

Sui Generis (soo-ee JEN-urr-iss); Latin
Definition: Unique.
Usage: That family's rattletrap station wagon — held together with duct tape
— is sui generis.
What the Experts Say
"In French the adjective passé can still mean 'past it,' 'obsolete,' or 'no
longer much good,' but exclusively in reference to melons. So if you talk
about a person or a show as passé, it's either a delightful metaphor — in the
sense of 'as overripe as a rotting melon' — or it's just a boo-boo."
— David Bellos, professor and chair of romance languages and literature at
Princeton University

"People tend to misunderstand that the Latin words alumnus and alumni are
male nouns. The female forms are alumna and alumnae."
— Mike Agnes, editor in chief of Webster's New World College Dictionary

"Yo is not just a greeting from Sylvester Stallone; it is the
first-person-singular subject pronoun for 'I' in Spanish."
— Kellye Church, Spanish lecturer at the University of North