MUGGINS

fool, sap, saphead, muggins, tomfool

(noun) a person who lacks good judgment

Source: WordNet® 3.1

Noun

muggins (countable and uncountable, plural mugginses)

A fool or idiot (especially as an ironic way of referring to oneself).

(cribbage) The act of stealing another player's points because they either mis-pegged or counted up incorrectly.

(uncountable) A game of dominoes in which the object is to make the sum of the two ends of the line some multiple of five.

(uncountable) A card game based on building in suits or matching exposed cards, the object being to get rid of one's cards.

Source: Wiktionary

Mug"gins, n. [Etym. unknown.]

1. A game of dominoes in which the object is to make the sum of the two ends of the line some multiple of five.

2. A game at cards which depends upon building in suits or matching exposed cards, the object being to get rid of one's cards.

Mug"gins, v. t.

Definition: In certain games, to score against, or take an advantage over (an opponent), as for an error, announcing the act by saying "muggins."

Source: Webster’s Unabridged Dictionary 1913 Edition