Fatherly (8)
I believe the answer is:
paternal
'fatherly' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for paternal that I've seen before include "Fatherly in prenatal way" , "Fatherly in pre-natal mode" , "Of one's father" , "protective interest" , "Related on the father's side" .)