inquiétitude — WORRY

[uhn-KEE-ETT-ee-tewd] (n. f.) "Be quiet! Quiet down! Quiet please. He was a quiet guy, a little too quiet... On a quiet street... She lived a quiet life... Before the hold-up, the criminal had remained quiet for years... The kid had a quiet conscience." Quiet is one of those English words used in myriad ways, to express something a little different every time, a lovely feature of this pliable language. Of course, quiet comes from the French word quiéte, which is the sort of word you can easily alter with suffixes and prefixes. Inquiéte means she is worried. But if you add the suffix -itude, which is the French equivalent of -ness (think of attitude, borrowed French for aptness), you get the noun inquiétitude (un-quiet-ness) which means worry.

BONUS: A commonly used American colloquialism is no problem, or for the Terminator no problemo. The French equivalent of this is t'inquiétes [tuhn-KEE-ETT]. It's short for ne t'inquiéte pas.

incendie — FIRE

[enh-so(n)-DEE] (n. m.) When someone writes an incendiary report it does not means they're going to use the paper and set something on fire with it, although, if they followed the word to the letter, that's exactly what they're letting on. The word actually comes from the Latin incendiarius which means to set on fire. The French, in their inflexibility with language, stuck with the Latin and still use the word incendie to mean a fire (as opposed to just the element of fire.)