Second badger's a problem (4)
I believe the answer is:
snag
'a problem' is the definition.
(thesaurus)
'second badger's' is the wordplay.
'second' becomes 's' (common abbreviation).
'badger' becomes 'nag' (I've seen this before**).
's'+'nag'='SNAG'
(Other definitions for snag that I've seen before include "Temporary hold-up" , "Disadvantage - small hole in fabric" , "Rip or tear" , "Hidden obstacle or catch" , "Jag" .)