mon français est mauvais ("moh[n] frah[n]-seh eh mo-veh")
To say that your French is bad in French, you simply just say, Je parle mal français. In another case, if your French is very bad, you would say, Je parle très mal français.
Un mauvais rêve
As an adjective, as in, "This is a bad movie," "bad" translates to "mauvais" in French. In the sentence, "She feels bad," "bad" translates to "mal" in French.
Bad is 'mauvaise' and girl is 'fille'.
I don't know of any French equivalent of "noob/n00b" (internet game-speak for a bad player or "newbie"). You could say "débutant" or "bleu". French gamers would generally understand "noob" anyway, though.
"Pas mal" is how you say "not bad" in French.
bad - mauvais
Mauvais.
I am not bad is "je ne suis pas mauvais / mauvaise" in French.
The way to say "bad" in french is mauvais (masculine) or mauvaise (feminine)
"Bad teacher" in French is "mauvais professeur."
In French, bad wolf translates to "méchant loup."
malfaiteur
One would say "dommage".
Mauvais emplois.
mauvais endroit
mauvaise chansson