Laugh about a large ring (4)
I believe the answer is:
halo
'ring' is the definition.
(I know that ring can be written as halo)
'laugh about a large' is the wordplay.
'laugh' becomes 'ho' (representation of a laughing sound).
'about' means one lot of letters goes inside another.
'large' becomes 'L' (eg in clothes sizes).
'a'+'l'='al'
'ho' enclosing 'al' is 'HALO'.
(Other definitions for halo that I've seen before include "Aura representing saintliness" , "Luminous ring" , "Circle of (holy) light" , "Light around sun, saint" , "Aura round admired person" .)