THESAURUS
pit against
aggravate, alienate, bump heads, come between, confront, contend, contrapose, contraposit, contrast, counteract, disaffect, disunite, divide, estrange, face, fan the flame, front, irritate, lie opposite, light the fuse, make trouble, match, meet head-on, oppose, polarize, pose against, provoke, put in opposition, separate, set against, set at odds, set at variance, set on, set over against, sic on, sow dissension, stand opposed, stand opposite, stir up trouble, subtend
ROGET THESAURUS
pit 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.
Discord
VB
be discordant, disagree, come amiss, clash, jar, jostle, pull different ways, conflict, have no measures with, misunderstand one another, live like cat and dog, differ, dissent, have a bone to pick, have a crow to pluck with, fall out, quarrel, dispute, litigate, controvert, squabble, wrangle, jangle, brangle, bicker, nag, spar, have words, with, fall foul of, split, break with, break squares with, part company with, declare war, try conclusions, join issue, put in issue, pick a quarrel, fasten a quarrel on, sow dissension, stir up dissension, embroil, entangle, disunite, widen the breach, set at odds, set together by the ears, set against,
pit against, get into hot water, fish in troubled waters, brawl, kick up a row, kick up a dust, turn the house out of window, be discordant, jar.