He bowed slightly to K.'s uncle, who appeared very flattered to make this new acquaintance, yet, being by nature incapable of expressing obligation, requited the Clerk of the Court's words with a burst of embarrassed but raucous laughter.
To repay; in a good sense, to recompense; to return (an equivalent) in good; to reward; in a bad sense, to retaliate; to return (evil) for evil; to punish