Heading for home? Unable to leave it (10)
I believe the answer is:
housebound
'unable to leave it' is the definition.
I can't judge whether this defines the answer.
'heading for home?' is the wordplay.
'heading' says to put letters next to each other (some letters go in front of or head others).
'for' becomes 'bound' (I can't justify this - if you can you should believe this answer much more).
'home?' becomes 'house' (homing is a kind of housing).
'bound' after 'house' is 'HOUSEBOUND'.
(Other definitions for housebound that I've seen before include "kept at home" , "unable to get out" , "Always in" .)