MEANING: noun: A substance producing harmful effects in someone because it is believed to be harmful, but which in reality is harmless.

ETYMOLOGY: From Latin nocebo (I will harm), from nocere (to harm). Modeled after its antonym placebo (I will please). Earliest documented use: 1961.

NICE, BO - well done, Ms Derek

NO CEO - the head of the company just got canned

NO SEBO - a first-class gringo trying to say "I don't understand" in Spanish