antagonize
attack
battle
be antipathetic
be at cross-purposes
be contrary to
be inimical
be opposed to
beat against
belie
call into question
challenge
clash
collide
conflict
conflict with
confute
contest
contradict
contrapose
contrast with
contravene
controvert
counter
counteract
counterattack
counterbalance
countercheck
counterpoise
counterpose
countervail
counterwork
cross
deny
fight
gainsay
go against
go counter to
impugn
interfere with
juxtapose in opposition
lock horns
meet head-on
militate against
negate
offset
oppose
play at cross-purposes
rebut
oppugned
oppugning
oppugns