Head working and working to take over Independent (5)
I believe the answer is:
onion
'head' is the definition.
(I've seen this before)
'working and working to take over independent' is the wordplay.
'working' becomes 'on'.
'and' means one lot of letters go next to another (I've seen this in other clues).
'working' becomes 'on'.
'to take over' means one lot of letters goes inside another.
'independent' becomes 'i'.
'on' put after 'on' is 'onon'.
'onon' enclosing 'i' is 'ONION'.
(Other definitions for onion that I've seen before include "Plant with edible bulb" , "Pungent vegetable" , "Eye-watering vegetable" , "Head (slang); vegetable" , "Bulb used in cooking" .)