Rush Limbaugh -- DISSIN' HOWARD STERN ... 'I Don't Know Who You're Talking About'

Rush Limbaugh is not a fan of Howard Stern ... and last night, he issued a subtle diss to his radio rival ... and it was all caught on video.

Rush was leaving Toscana in L.A. when we asked what he thought about Jesse Ventura telling the media he wants to run for President in 2016 with Howard Stern as his running mate.

And what did Rush have to say about it ... "Who? I don't know who you're talking about."

Boom.

Limbaugh and Stern ain't exactly on friendly terms -- in the past, Stern has referred to Limbaugh as an "idiot," a "loon" and said "he's insane." Stern has also said the guy is "out of touch."