Cuck meaning : A cuckold. A weakling. One who acts against one's own interests, or that of one's own race, gender, class, religion, etc. To cuckold, to be sexually unfaithful towards. To weaken or emasculate. To fool and thus lower the status of, to exploit the trust or tolerance of (to one's own benefit and the other's disadvantage); to make into a cuck (one who acts against their own interests).