loner (n.)

• alien
• anchorite
• ascetic
• careerist
• case
• character
• crackpot
• crank
• eccentric
• egotist
• eremite
• fanatic
• hermit
• hobo
• hog
• homebody
• individualist
• invalid
• isolationist
• kook
• marabout
• maverick
• monopolist
• narcissist
• natural
• nonconformist
• nut
• oddball
• oddity
• original
• outcast
• outsider
• pariah
• recluse
• screwball
• self-seeker
• shut-in
• solitaire
• solitary
• solitudinarian
• stay-at-home
• stylite
• temporizer
• timeserver
• tramp
• type
• zealot