it is a noun labelled to someone who likes to "mac" a dad (make sexual relations with someone's father) in order to get another party jealous.

it is also a name given to gays/homosexual in the city of winnipeg.
hey robert, i just arranged a Mcdadi with John because his wife was giving me an evil eye.

oh my lord this baby will turn out to be a McDadi.
by supertimemon March 6, 2009
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