cooperate

v.

1. To work together

   unite, combine, collaborate, concur, conspire, concert, pool, join forces, act in concert, stand together, hold together, stick together, team up, show a willingness, comply with, join in, go along with, make common cause, unite efforts, share in, second, cast in one's lot with, take part, be a party to, collude, connive, act jointly, work in unison, interact, participate, work side by side with, side with, join hands with, fraternize, play along with*, play fair*, throw in with*, fall in with*, be in cahoots*, chip in*, pitch in*, stand shoulder to shoulder*, pull together*, play ball*; see also agree, join 2, unite 1.

   Antonyms act independently, differ*, diverge. *

2. To help

   contribute, second, espouse, uphold, befriend, succor, lend oneself to, share, lend a hand, go out of the way for, assist, relieve, reinforce, promote, further, forward, advance, sustain, back up, stand by, side with; see also encourage 1, help 1, support 2.

   Antonyms hamper, hinder*, harm.