drop-in vs walk-in

drop-in

adj
  • Allowing people to drop in; that is, to visit casually, without an appointment. 

  • Provided for short-term use. 

  • Fit to substitute for some element in a complex system without changes to the existing infrastructure. 

noun
  • The act of dropping in; that is, taking a wave that another surfer is already riding. 

  • A place that can be visited casually, without an appointment. 

  • One who casually drops in (visits unannounced or without appointment). 

  • An informal event that does not require booking in advance. 

walk-in

adj
  • That people may enter without a prior appointment. 

  • Accessed by walking, either exclusively, as a campground, or together with drive-in access, as at some drive-in movie theaters. 

  • Gaining access through unlocked doors. 

  • Designed to be possible to walk into (without stepping over a ledge, etc). 

  • Spacious enough to walk into. 

noun
  • A demonstration or protest in which the participants assemble outside a facility, gain media exposure, and enter the facility in unison. 

  • A relatively small room (such as a closet or pantry) or refrigerator or freezer that is spacious enough to walk into. 

  • A customer, job applicant or similar who visits a restaurant, medical facility, car dealership, etc. without a reservation, appointment, or referral. 

  • A relatively larger room or (especially) an apartment that is entered directly, not via an intervening passage or lobby. 

  • A person whose original soul has departed the body and been replaced with another. 

  • A facility or an event that principally handles customers who do not have an appointment. 

  • A defector (or similar) who walks into an embassy (etc) unannounced. 

  • A facility accessed on foot rather than by car, usually contrasted to drive-in. 

How often have the words drop-in and walk-in occurred in a corpus of books? (source: Google Ngram Viewer )