of or pertaining to persons who walk into a place from the street, especially irregularly or without an appointment: walk-in customers; walk-in sales; a walk-in patient.
large enough to be walked into: a walk-in kitchen.
a person, as a customer, patient, or interviewee, who arrives without an appointment: Many of the clinic's patients are walk-ins who suddenly need help.
something large enough to be walked into, as a closet.
an assured victory in an election or other contest.
1925–30; adj., noun use of verb phrase walk in