THESAURUS
work against
antagonize, be antipathetic, be inimical, beat against, clash, collide, conflict, conflict with, confute, contradict, contrapose, contravene, counter, counteract, counterattack, counterpose, countervail, counterwork, cross, go against, go counter to, interfere with, lock horns, meet head-on, militate against, oppose, oppugn, resist, run against, run counter to, swim upstream
ROGET THESAURUS
work against
Opposition
VB
oppose, counteract, run counter to, withstand, control, hinder, antagonize, oppugn, fly in the face of, go dead against, kick against, fall afoul of, run afoul of, set against, pit against, face, confront, cope with, make a stand, make a dead set against, set oneself against, set one's face against, protest against, vote against, raise one's voice against, disfavor, turn one's back upon, set at naught, slap in the face, slam the door in one's face, be at cross purposes, play at cross purposes, counterwork, countermine, thwart, overthwart,
work against, undermine, stem, breast, encounter, stem the tide, breast the tide, stem the current, stem the flood, buffet the waves, beat up against, make head against, grapple with, kick against the pricks, contend, do battle with, do battle against, contradict, contravene, belie, go against, run against, beat against, militate against, come in conflict with, emulate, rival, spoil one's trade.