Grant Hill -- Sorry Shaq ... Your Shoe Was The Ugliest EVER

Shaquille O'Neal is about to learn how Grant Hill's opinion tastes ... 'cause the ex-NBA star and new part owner of the Hawks just called out Shaq's signature bball shoe ... as the ugliest of all time.

Grant was out at LAX looking sharp when our camera guy asked him which shoe was the most dreadfully ugly pair of stompers ever to grace an NBA court.

Check out the clip -- Hill bypasses all the usual suspects (we're looking at you Kobe II's) and hits The Diesel right where it hurts, saying his kicks take the cake when it comes to fugly footwear.

Ugly? Maybe. Size 22? Definitely. Tread lightly Grant.