Walk-in

Adjective

1. (of a place) that people may enter without a prior appointment
2. (of a thief) that gains access through unlocked doors
3. (of a defector etc) that walks into an embassy etc unannounced
4. (US, of a cinema) not a drive-in
5. (of a room) entered without an intervening passage

Full definition of walk-in

Noun

1. a walk-in room or closet
2. a walk-in defector etc.
3. (parapsychology) A person whose original soul has departed the body and been replaced with another.
4. A customer who visits a restaurant, hair salon, etc. without a reservation.
• 1996, Kazuo Nishiyama, Welcoming the Japanese visitor: insights, tips, tactics (page 85)An astute manager will have a table or two set aside for important regular customers or demanding walk-ins.