Lungs bit dodgy when it's hectic (8)
I believe the answer is:
bustling
'it's hectic' is the definition.
(thesaurus)
'lungs bit dodgy' is the wordplay.
'dodgy' indicates anagramming the letters (a dodgy or wrong order of the letters).
'lungs'+'bit'='lungsbit'
'lungsbit' with letters rearranged gives 'BUSTLING'.
'when' acts as a link.
(Other definitions for bustling that I've seen before include "busy" , "Acting fussily" .)