say it: WAW-kin
walk-in is a noun and adjective meaning "person who walks in without having an appointment". It carries 5 recorded senses.
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”
Definitions, synonyms and semantic relations for walk-in come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.