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pants that are worn by males that are too hot are too tight; usually refered in the first person
"man I should not have worn these sperm killers to the golf course today."
by peeroni May 11, 2008
Very tight, compressing pants that deplete your seamen count.
"Dude, that guy had some major sperm killers on at H&M"
by iceteaIceedout September 07, 2014