the term underlay is simply another word for a jumpoff/whore that you have sexual relations with, the term originates in the Bay area but is use in the south as well
Man 1:hey cuzz, imma have to call maxine up
Man 2: yeah my underlay
by The Abbot *7 July 21, 2010
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This is when someone spins you that you made plans with to go be with someone else. A great lie told to keep oneself out of the dog house or look good in front of a certain group of people. Giving an elaborate excuse that's usually not true for why you can't , didn't , or won't be able to do something.
Saturday I had two girls coming over at the same time so I had to think quick and told one that my cousin was in the hospital but that was just the "underlay for the overplay" so I didn't get busted.
by Da Real Deal 1 November 6, 2012
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It's a material that is applied under another material for its proper application.
- Ah, dude, your underlayment is thick
-Um, yah, it's cork.
-Cool
by Mistafil June 27, 2017
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