From the saying "That's a Mact". Basically, it's a fact which is of doubtful authenticity and may well have been completely made up by anyone named Matt.
Matt: "I drive an Audi TT, am half-Columbian and have awesome dimples."
Everyone else: "And that's a Mact!"
by Lord Tennyson January 1, 2012
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Pronounced "macked"

Word used in reference to Ecstasy or Thizz and can be used in many fashions. It is in reference to the bay area rapper Mac Dre (t.i.p.) It can be used in reference of the drug itself or while rolling. It is important to use only if sure of the high purity of the drug. The thizz version of chronic

please also see gnarmact
Yayo and I are definetely gettin mact tonight before we hit the club.
by sickbeats May 17, 2007
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