trash talk 
US informal
noun [mass noun]
Insulting or boastful speech intended to demoralize or humiliate a sporting opponent: he heard more trash talk from the Giants before the game than during the game...
- Despite the derision that its scripted matches, over-the-top trash talk, and outlandish characters sometimes inspire, professional wrestling is big business.
- I think it sells a lot better for TV, but I used to look at the old fighters like Joe Louis and I hardly ever heard trash talk at their press conferences.
- We're talking bluster and light-hearted trash talk as we each announce our picks.
verb [no object] (trash-talk)
Make boastful or insulting remarks in order to demoralize or humiliate a sporting opponent: Westering’s players do not swear or tussle or trash-talk [with object]: people were going to trash-talk us until we started to win (as adjective trash-talking) trash-talking foreign junk-bond dealers...
- Even further, stations themselves often trash-talk about the other stations in a broadcast market.
- We can trash-talk all we want in-game, but there's very little that's gained by taking that outside of the competitive arena.
- He's not going to put it in your face or trash-talk or do anything like that, because that just wouldn't be his style.
Derivatives
trash talker
- I was never a big trash talker in college, but if somebody was a bit cocky, I let them know it.
- I'm really not much of a trash talker.
- He isn't popular among opponents - he's a trash talker who will do anything to gain a competitive edge - but he definitely is one of the two or three best players on the team.
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