Answer:

LIFER

Answer	Crossword Clue
LIFER	Big house denizen
LIFER	Permanent con
LIFER	One who can't get out

LIFER	Committed type, say
LIFER	Career soldier
LIFER	Certain inmate
LIFER	Military careerist
LIFER	Army careerist
LIFER	One envying parolees
LIFER	One who'll always be in
LIFER	Unpardonable one?

LIFER	Permanent pen pal?
LIFER	Career military person
LIFER	One ineligible for parole, probably
LIFER	One who never gets out
LIFER	Longtime employee
LIFER	Big house occupant?
LIFER	Pen pal, perhaps?
LIFER	Long sentence server

LIFER	Prisoner for good
LIFER	One with much time on his hands
LIFER	Permanent prisoner
LIFER	The Birdman of Alcatraz, for one
LIFER	One always in a stir?
LIFER	One whose sentence goes on and on
LIFER	Constantly confined con
LIFER	Armed forces careerist

LIFER	Permanent resident
LIFER	Career officer
LIFER	One committed to a military career
LIFER	Birdman of Alcatraz was one
LIFER	Long-term inmate
LIFER	Career GI
LIFER	Committed careerist
LIFER	Many an admiral

LIFER	Inmate who's never getting out
LIFER	One who never gets out?
LIFER	One with an endless prison term
LIFER	Full-time inmate: Slang.
LIFER	Long-term inmate.