It has always amused me how far the word "cow" can get you in the French language. "Cow" may already be a funny word, no matter what your motive is to guffaw, but the extent of the usage of it in French is another thing. It's fairly frequently used, mostly in a slang or colloquial way, rather than in reference to the animal. I'll explain some useful examples of both. Well, here's a quick French lesson. You will be quizzed on this. Today's topic: vache.
NOUN:
As a noun vache, has pretty straightforward meanings, which aren't too confusing when understood in context.
La vache - cow, cowhide feminine
"Cow" would be the literal meaning of la vache, but there is much more to the word than that. In slang, it is used as an insult. When using this word to speak of a woman, it can roughly equal "bitch". When describing a man, it can equal something around the lines of "swine" or "rat". One can also call a policeman this, which would be like calling him a flatfoot. Generally speaking, vache can also mean gull or sucker.
Also:
Vache au eau - canvas bucket
Vache au lait - milking cow
ADJECTIVE:
As an adjective, this word gets a little interesting... very interesting... insane]. Basically put, when describing something, it can mean anything. Well, almost anything. It can express admiration, or liking such as in this instance: Elle est vache (She is cool/neat-o). Or it can express dislike: Ça? C'est vache! Yharrrg! (That? It's stupid/terrible). Or indifference: La vache? Oh, elle est... euh... vache... (The cow? Oh, it's... meh...) Or you can just switch those all around. You can't really pound out a concrete meaning. One just has to figure these things out by tone and context. You can use it as your all-purpose French adjective, but just don't over do it, d'accord?
There are also some non-slang uses of vache as an adjective. It can also be used, for example, like this: une question vache, which would mean "an embarrassing question". Another use is illustrated here: une dame vache, "an irritable lady".
Also:
En vache - leather
ADVERB:
Okay, so "vache" can't really be used as an adverb as is, but adding the ending -ment will do the job. Vachement is generally used to express enthusiasm. Instead of translating J'aime bien la vache, elle est vachement vache! as "I am fond of the cow, it is cowly cow!" I would translate it, based on context, more like this: "I am fond of the cow, it is tremendously cool!" See? This is much more easy to use and understand than its adjective form.
INTERJECTION:
La vache! - Damn it!
EXPRESSIONS:
Manger de la vache enragée
Literally: To eat of the enraged cow
Figuratively: Not to have a red cent to one's name
Parler français comme une vache espagnole
Literally: To speak French like a Spanish cow
Figuratively: To murder the French language
Great, huh? Now you shall no longer be the tête de bois that you once were. Get out there and show your new command over the word vache! Or don't.
Please /msg me if you want to contribute more uses of vache to this writeup or want to yell at me about my French grammar. | 
