Insect is not her problem (6)
I believe the answer is:
hornet
'insect' is the definition.
(hornet is a kind of insect)
'not her problem' is the wordplay.
'problem' indicates anagramming the letters.
'not'+'her'='nother'
'nother' is an anagram of 'HORNET'.
'is' acts as a link.
(Other definitions for hornet that I've seen before include "Vespa" , "A large wasp with serious sting" , "Stingy type" , "Large stinging wasp" , "Run through" .)