Daughter working for boss is a stupid person (10)
I believe the answer is:
dunderhead
'stupid person' is the definition.
(I've seen this before)
'daughter working for boss' is the wordplay.
'daughter' becomes 'd'.
'working for' becomes 'under' (I've seen this in other clues).
'boss' becomes 'head' ('head' can be a synonym of 'boss').
'd'+'under'+'head'='DUNDERHEAD'
'is a' acts as a link.
(Other definitions for dunderhead that I've seen before include "Idiot" , "Dunce" , "dumbass?" , "fool" , "Stupid person" .)