Grand beers cause fits of laughter (5)
I believe the answer is:
gales
'fits of laughter' is the definition.
Although both the answer and definition are plural nouns, I can't see how they can define each other.
'grand beers' is the wordplay.
'grand' becomes 'g' (G is short for grand as in a thousand).
'beers' becomes 'ales' (ale is a type of beer).
'g'+'ales'='GALES'
'cause' is the link.
Can you help me to learn more?
(Other definitions for gales that I've seen before include "High winds" , "Force 7 to 10 winds" , "Weather conditions" , "They're force 7 to 10 on the Beaufort scale" , "Tempests and squalls" .)