Tank Abbott -- RIPPED BY UFC LEGENDS ... You're a Drunken Moron

Tank Abbott must be WASTED DRUNK if he thinks he could take Ronda Rousey in a fight ... so says UFC legend Frank Shamrock.

Shamrock tells us he's heard about Tank's chauvinistic $100,000 "Make Me a Sandwich" challenge to female fighters ... and quite frankly, thinks the UFC legend is out of his boozed up mind.

"I think Tank spends a little too much time on the bar stool," Shamrock says ... "He'd be submitted in 20 seconds. He'd be bent over in the ring throwing up all the alcohol."

And he's not the only UFC legend who feels that way ... we also spoke with Vitor Belfort who says, "I think Tank is wrong. He's a great fighter, but I think Ronda could beat him."

"Speed always beats size. Thunder makes noise, lightening does the damage."

For the record, Tank says no woman has taken him up on his challenge yet -- but insists he's dead serious about it.