Translation:My cat steals butter from the refrigerator.
In British English, "I robbed him of his butter", "I robbed him by taking his butter" and "I robbed him" are all considered to be grammatically correct, but "I robbed the butter from him" is considered to be bad English (although it does nonetheless occur in spoken colloquial English). "Rob" is applied only with the victim as object: it is the owner of the item that is robbed. The item is not robbed.
'Steal' is a more passive term than 'rob.' Rob is implying that you broke in somewhere and stole.
so, if the fridge is closed, it's a robbery; if you left it open, it's stealing? ; )
Rob is not correct because in English rob and steal have different meanings. You rob a place, but you steal a thing from a place. The correct way to use rob here would be to say "my cat robbed the refrigerator of the butter." Otherwise, the cat can only steal butter.
Agreed. At least in British English you rob the owner by stealing their possessions, but you do not rob the possessions or steal the owner! I am not sure if this applies equally in all variations of English.
Can roubar also mean "to rob"? That's what the cognates would seem to indicate (rob/roubar).
Yes, and colloquially in the US, you do hear "what did he rob?" "He robbed money," "he robbed cash"... even if correctly, it should be "what did he rob them of," "he robbed the bank of money," "he robbed the old lady of cash." They probably should at least accept the grammatically-correct, "my cat robs the fridge of butter."