Ginger's wrong to laugh so! (7)
I believe the answer is:
snigger
'laugh so' is the definition.
'snigger' can be an answer for 'laugh' (sniggering is a kind of laughing). I am not sure about the 'so' bit.
'ginger's wrong' is the wordplay.
'wrong' indicates an anagram.
'gingers' is an anagram of 'SNIGGER'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for snigger that I've seen before include "Laugh mockingly" , "Surreptitious laugh" , "Suppressed laugh" , "Laugh slyly" , "Dirty laugh" .)