Meaning : Person who walks in without having an appointment.
Example :
The emergency room was overrun with walk-ins.
Meaning : An operative who initiates his own defection (usually to a hostile country) for political asylum.
Meaning : An assured victory (especially in an election).
Synonyms : waltz
Meaning : A small room large enough to admit entrance.
Meaning : (of e.g. closets or refrigerators) extending very far enough back to allow a person to enter.
Example :
A deep walk-in refrigerator.
Walk-in closets.