Reprimand insect biting rodent (6)
I believe the answer is:
berate
'reprimand' is the definition.
(I know that reprimand can be written as berate)
'insect biting rodent' is the wordplay.
'insect' becomes 'bee' (bee is a type of insect).
'biting' indicates putting letters inside (some letters bite or swallow others).
'rodent' becomes 'rat' (rat is a kind of rodent).
'bee' placed around 'rat' is 'BERATE'.
(Other definitions for berate that I've seen before include "Scold, censure" , "Rebate (anag.)" , "Condemn" , "Reprimand" , "Scold harshly" .)