gain-

Prefix meaning "against", "contrary to", "in opposition to", "counter-".

gainsay, gainstand, gainstay, gainstrive

Prefix denoting reciprocal action; "in return"; "counter-".

gainclap, gaingive, gainyield

Prefix denoting restoration or a return to a previous state; "back again".

gainbuy, gaincover, gaintake

Prefix denoting repetition; "over again"; "anew"; again-.

gainrising, gaincoming