To bring down the mood of a party or social situation by being excessively awkward or depressing. Similar to being a Debbie Downer or Negative Nancy.
"This party was awesome until that douche came and welched it up."
"Dude, you're being such a welch."
"Dude, you're being such a welch."
by douchedecon October 4, 2008

The act of saying your are going to stream, then not streaming without notice and blaming it on being sick or injured - first used by viewers of lospollostv
"person 1Bro los welched again? person 2 Yep he welches almost every goddamn day, its like he is programmed to welch"
by lospollostvviewer March 18, 2017

YOU: "I'll make a bet that Carlton suck and miss the 8, loser has to suck Suzis penis."
BlackFlag: "Carlton will win the premiership you douche, i'll take your bet"
Carlton go on to stink up the entire competition, blackflag loses the bet, and ignores that the bet was ever placed. Making him a dirty welch and the lowest form of life in the universe.
BlackFlag: "Carlton will win the premiership you douche, i'll take your bet"
Carlton go on to stink up the entire competition, blackflag loses the bet, and ignores that the bet was ever placed. Making him a dirty welch and the lowest form of life in the universe.
by Blissid April 28, 2010

by contractorpeon March 2, 2005

that fucker welched on the Giants - Eagles (he bet they wouldn't cover the spread and they fucking did!)
by danielwebster June 6, 2007

by Fruit Snacks August 14, 2018
