1 a person who gains weight [syn: weight gainer]
2 a person who gains (gains an advantage or gains profits); "she was clearly the gainer in that exchange"
3 a dive in which the diver throws the feet forward to complete a full backward somersault and enters the water feet first and facing away from the diving board [syn: full gainer]
A gainer is slang term for an acrobatic skill in which the acrobat performs a backwards somersault while still moving forward. In diving, this is known as reverse rotation (as opposed to front, back, or inward). Many stunt performers and martial artists are capable of performing a similar skill on the ground, sometimes in combination with a midair inverted kick.