癪 （しゃく） cause of offense, cause of offence, annoyance, peeve, spasms, convulsions, cramps

癪にさわる （しゃくにさわる） to irritate, to grate on one's nerves, to aggravate, to be galling, to be invidious

小癪 （こしゃく） impudent, cheeky