second-hand condominium; previously owned apartment
Refers to a condominium unit that is being resold, not brand-new. Common in real estate contexts.
I'm looking for a second-hand condominium in Tokyo.
中古マンション refers to a previously owned, used condominium, the direct opposite of a newly built 新築マンション.
Compound of 中古 (second-hand) and マンション (condominium, from English 'mansion').