Bad lads outside clubs causing injury (5)
I believe the answer is:
scald
'injury' is the definition.
(I know that scald is a type of burn)
'bad lads outside clubs' is the wordplay.
'bad' indicates an anagram.
'outside' is an insertion indicator.
'clubs' becomes 'c' (abbreviation used in card games such as bridge).
'lads' anagrammed gives 'sald'.
'sald' enclosing 'c' is 'SCALD'.
'causing' acts as a link.
(Other definitions for scald that I've seen before include "Injure with hot liquid" , "Injure with steam" , "Burn with hot liquid" , "Heat (milk) to near boiling point" , "Burn with water" .)