[back.lash] n (1815) 1 a: a sudden violent backward movement or reaction b: the play between adjacent movable parts (as in a series of gears); also: the jar caused by this when the parts are put into action
2: a snarl in that part of a fishing line wound on the reel
3: a strong adverse reaction (as to a recent political or social development) -- back.lash.er n