Godan verb with 'u' ending, Intransitive verb
to negotiate (with someone about); to talk over (something with); to tackle someone (about); to haggle; to bargain
その事で先生に掛け合ってもらうように彼女を選んだ。We elected her to approach our teacher on the matter. Godan verb with 'u' ending, Transitive verb
to throw on each other; to splash (water) on each other; to pour on each other
Also written 懸け合う【かけあう】