Definitions for walk in
person who walks in without having an appointment
"the emergency room was overrun with walk-ins"
an operative who initiates his own defection (usually to a hostile country) for political asylum
an assured victory (especially in an election)
a small room large enough to admit entrance
(of e.g. closets or refrigerators) extending very far enough back to allow a person to enter
"a deep walk-in refrigerator"; "walk-in closets"
enter by walking
"She walks in at all hours, as if she lived here"