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