The term MEAN MUTT is composed of two crossword solutions, BITER (5 letters) and CUR (3 letters). BITER is a word used to describe someone or something that bites or has a tendency to bite. CUR is an informal term for a dog, usually one that is wild, unkempt, or of a mixed breed. Together, these two words form the phrase MEAN MUTT, which is used to describe a dog that is aggressive, unfriendly, and potentially dangerous.