Refers to a period of time in which a person has slept no more than a combined 14 hours out of the last 7 days. It has been said that someone who is truly piss tired could be urinated upon and lack the energy to do anything about it.
John: Hey Rick, did you see Bob take advantage of John when he was piss tired after finals?
Rick: Yes, he was completely soaked.
by Andrrew July 26, 2006
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