lit. 'wrongly-performed-ness' (ku+krta+ya),
i.e. scruples, remorse, uneasiness of conscience, worry, is one of the karmically unwholesome (akusala) mental faculties (Tab. II) which, whenever it arises, is associated with hateful (discontented) consciousness (Tab. I and III, 30, 31).
It is the 'repentance over wrong things done, and right things neglected' (Com. to A. I).
Restlessness and scruples (uddhacca-kukkucca), combined, are counted as one of the 5 mental hindrances (nīvarana).