Go wild with game knight having great laugh (3,4)
I believe the answer is:
run riot
'go wild' is the definition.
(I've seen this before)
'game knight having great laugh' is the wordplay.
'game' becomes 'RU' (rugby union).
'knight' becomes 'n' (chess abbreviation).
'having' is a charade indicator (letters next to each other).
'great laugh' becomes 'riot' (riot is a kind of laugh. I am not sure about the 'great' bit.).
'ru'+'n'+'riot'='RUN RIOT'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for run riot that I've seen before include "Behave wildly and without restraint" , "Act wildly" , "Of mob, throw off all restraint" , "Act wantonly, without restraint" , "go crazy" .)