carper (n.)

early 13c., "to talk, speak, tell," from Old Norse karpa "to brag," which is of unknown origin. The meaning turned toward "find fault with, complain," particularly without reason or petulantly (late 14c.) probably by influence of Latin carpere "to slander, revile," literally "to pluck" (which is from PIE root *kerp- "to gather, pluck, harvest"). Related: Carped; carping.