Verne Troyer -- Farts on NFL Legend's Wife ... In Protest

Verne Troyer let his ass do the talking for him during an argument with Hines Ward's wife -- ripping a fart on the NFL star's spouse in protest ... and it was all caught on video.

It all went down on Wednesday night's episode of "Celebrity Wife Swap" -- when Hines' wife Lindsey Georgalas moved in with the "Austin Powers" star and tried to redecorate his game room.

But Troyer HATED the feminine touches Lindsey was trying to put in the room -- and to show his discontent ... the little guy let out a big one.