Laughter about a bounder back in trouble (8)
I believe the answer is:
headache
'trouble' is the definition.
(thesaurus)
'laughter about a bounder back' is the wordplay.
'laughter' becomes 'hehe' ('hehe' is the sound of laughter).
'about' indicates putting letters inside.
'bounder' becomes 'cad' (synonyms).
'back' shows that the letters should be reversed in order.
'cad' back-to-front is 'dac'.
'a'+'dac'='adac'
'hehe' going around 'adac' is 'HEADACHE'.
'in' acts as a link.
(Other definitions for headache that I've seen before include "Worry, trouble (colloq.)" , "Cause of worry or trouble" , "A pain in the brain" , "Major problem" , "nasty problem" .)