Indian father in pain (6)
I believe the answer is:
apache
'indian' is the definition.
(Apache is an example)
'father in pain' is the wordplay.
'father' becomes 'pa' (pa can mean dad or father).
'in' means one lot of letters goes inside another.
'pain' becomes 'ache' (ache is a kind of pain).
'pa' going within 'ache' is 'APACHE'.
(Other definitions for apache that I've seen before include "on the streets of Paris" , "N American Indian tribe or old Paris ruffian" , "Native American - French hoodlum" , "North American Indian tribe - Paris ruffian" , "American Indian of New Mexico and Arizona" .)