Staff removing the last of stacks (3)
I believe the answer is:
man
'staff' is the definition.
(as in staffing or manning a particular place)
'removing the last of stacks' is the wordplay.
'removing the last of' means to remove the last letter.
'stacks' becomes 'many' (stacks can mean many of something).
'many' with its final letter removed is 'MAN'.
(Other definitions for man that I've seen before include "Isle of . . ., . . . o' war" , "Dude" , "Geezer" , "Bloke" , "Adult human male" .)