Raucous laugh (6)
(Other definitions for guffaw that I've seen before include "Roar of laughter" , "Horselaugh" , "Belly laugh" , "Burst of loud, hearty laughter" , "way of expressing amusement" .)
(Other definitions for cackle that I've seen before include "Goose talk (sometimes cut)" , "Laugh harshly like witch" , "Loud laugh, like a witch perhaps" , "Laugh maniacally" , "Laugh raucously" .)