Bequeathed trainee a hammer (5)
I believe the answer is:
gavel
'a hammer' is the definition.
(I know that gavel is a type of beetle)
'bequeathed trainee' is the wordplay.
'bequeathed' becomes 'gave' (I've seen this in another clue).
'trainee' becomes 'l'.
'gave'+'l'='GAVEL'
(Other definitions for gavel that I've seen before include "Judge's hammer" , "Small hammer" , "Small mallet" , "Judicial hammer" , "Mason's hammer" .)