gain-

Prefix

Meaning

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

Source: en.wiktionary.org