(v. i.) To act or operate jointly with another or others; to concur in action, effort, or effect.

accord acquiesce act in concert act together affiliate agree ally alternate amalgamate answer to apportion assent assist associate assort with band band together bandy be agreeable to be consistent be dying to be eager be game be in cahoots be in league be of one be open to be partners in be quits with be ready be spoiling for be uniform with be willing change check chime club together coact coadunate coalesce cohere coincide collaborate collude combine commute compensate concert concord concur confederate conform conform with conjoin connive consent consist with consolidate conspire contribute correspond counterchange divide with divvy up with do business with dovetail engage exchange fall in together federate fit together fuse get back at get even with get heads together get together give and take go along with go even stephen go fifty-fifty go halvers go halves go partners go shares go together go with halve hang together happen together harmonize help hit hold together hook up incline interact interchange interlace interlock intermesh interplay intersect intertwine interweave interwork jibe join join forces join in join together keep together league league together lean lend a hand lock logroll look kindly upon make common cause match merge mesh mortise not hesitate to overlap parallel participate partner pay back permute play ball plunge into pull together put heads together reciprocate register register with requite respond respond to retaliate return return the compliment share share in sing in chorus sort with split the difference square square with stand together swap switch synchronize synergize tally team up throw in together tie in tie up trade transpose unite unite efforts work together would as leave would as lief