With a laugh, turning, reins the gee-gee in (7)
I believe the answer is:
snigger
'with a laugh' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'turning reins the gee-gee in' is the wordplay.
'turning' shows that the letters should be reversed in order.
'the gee' becomes 'g' ('g' can be a synonym of 'gee').
'gee' becomes 'g' (synonyms).
'in' means one lot of letters goes inside another.
'g'+'g'='gg'
'reins' placed around 'gg' is 'reggins'.
'reggins' written backwards gives 'SNIGGER'.
Can you help me to learn more?
(Other definitions for snigger that I've seen before include "Half-suppressed laugh" , "Laugh in a scornful way" , "Sly, stifled laugh" , "Laugh disrespectfully" , "Laugh mockingly" .)