The phrase "be against" has a range of synonyms that can convey a similar meaning, including "oppose," "resist," "object," "disapprove," "protest," "reject," "condemn," "repudiate," and "combat." When someone is against something, they are generally expressing a negative sentiment towards it. These synonyms all carry that same connotation, with some emphasizing more active opposition (such as combat) while others may simply indicate a less forceful disagreement (such as disapprove). Regardless of which synonym is used, the underlying implication is typically that the person in question is in some way opposed to or opposed to the idea or thing they are speaking about.