Gripper:-

a sarcastic remark, intended to provoke a response of some kind from the one it is directed at.
Gripper is normally intended as a general insult rather than as an accusation. Gripper has similar meanings and overtones, to American pejoratives like "jerk" or "jerk-off". One particular connotation is of someone self-obsessed or a show-off (usually male).

The Gripper gesture:-

Gripper may be indicated by a two-handed gesture, usually to an audience out of hearing range. It is shown by curling the the hand(s) into a loose fist and moving the hands together. This is equivalent to saying, "[you are a] gripper”.