Root out a bighead, being inhuman (5)
I believe the answer is:
robot
'root out a bighead being inhuman' is the definition.
I can't tell whether this defines the answer.
'root out a bighead' is the wordplay.
'out' means one lot of letters goes inside another.
'a bighead' becomes 'b' (head letter of 'big').
'root' placed around 'b' is 'ROBOT'.
Can you help me to learn more?
(Other definitions for robot that I've seen before include "Mechanism that can move like a human" , "Mechanical man" , "programmed servant" , "Programmable machine" , "Mechanical worker" .)