Yankees outfielder Clint Frazier SAVAGELY roasted the Houston Astros on his Twitch stream Tuesday ... throwing shade at the AL champs over their alleged use of trash bins in their 2017 cheating scandal.

The clip is pretty hilarious ... Frazier -- who's in the middle of a Call of Duty stream -- hits his virtual gun on some empty cans and says, "Two bangs, slider!"

After his avatar eventually goes down, he ribs the 'Stros some more, adding, "He said two bangs was a curveball and he banged twice and it was a heater!"

Of course, Houston is accused of stealing signs with video cameras 2 years ago and using dugout trash bins to relay the message to its hitters.

While it's a joking matter for Frazier -- who didn't make the Yankees' playoff roster when they played the Astros in the 2017 ALCS -- most guys in the MLB ain't laughin'.

Houston's penalty will reportedly be STEEP if it's found guilty ... and Yankees players and fans are still (rightfully) pissed over the whole deal.

In fact, CC Sabathia just said Tuesday he still sometimes wakes up "angry" over the whole issue!!!