The origin of the verb is uncertain; it is possibly borrowed from Norman groucier, from Old French groucier, grousser (“to grumble, murmur”) [and other forms] (whence grutch (“to complain; to murmur”) and grouch). The further etymology is unknown, but it may be derived from Frankish *grōtijan (“to make cry, scold, rebuke”) or of onomatopoeic origin. The noun is derived from the verb.