WWE Star William Regal -- The Worst Wrestling Costume Ever Is ...

Wrestling and bad costumes go hand-in-hand sometimes ... and WWE Superstar William Regal says when it comes to the worst of all time -- one wrestler's outfit blows away the competition.

From the Gobbledy Gooker to Max Moon ... the wrestling world has seen its fair share of bad costumes -- but on his way out of LAX Regal told us the costume Faarooq wore in his WWF debut (pictured below) is by far the worst ever.

In fact, Regal says Faarooq himself would admit it takes the cake for bad outfits.

DAMN!