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1.
to be bested by a far superior opponent in a game of wits. the loser often is humiliated and left in a deep downward spiral of low self esteem.

can also be used as a threat or slander such as:
"you got mcgilled"
"you have been mcgilled"
"i'm gonna mcgill you"
you: i think that insert argument here
opponent: well you are wrong because insert witty comeback

you have just been mcgilled
by glenforking October 25, 2009