Difficult individual to wake? Not entirely (7)
I believe the answer is:
onerous
'difficult' is the definition.
(thesaurus)
'individual to wake? not entirely' is the wordplay.
'individual' becomes 'one' (**).
'to wake?' becomes 'rouse' (I've seen this before).
'not entirely' means to remove the last letter.
'rouse' with its last letter taken away is 'rous'.
'one'+'rous'='ONEROUS'
(Other definitions for onerous that I've seen before include "Oppressive, difficult to bear" , "Burdensome as duty may be" , "Burdensome, taxing" , "Burdensome, heavy kind of duty" , "'Burdensome, not easily borne (7)'" .)