English

Noun

drop in ‎(plural drop ins)

1. One who arrives unannounced or without an appointment.

   The office was efficient, but not well equipped to handle drop-ins.

2. (surfing) the act of dropping in (see verb below). Often hyphenated drop-in.

   2005: Drop-ins can and do happen by accident, as well as through frustration and confusion in a crowded lineup. — surfline.com Surfology

Verb

drop in ‎(third-person singular simple present drops in, present participle dropping in, simple past and past participle dropped in)

1. (idiomatic) To arrive unannounced or with little or no warning; also, to visit without an appointment.

   I was in the garden covered with mud when my grandmother dropped in for a visit.‎

   • 1898, Winston Churchill, chapter 5, in The Celebrity:

     We made an odd party before the arrival of the Ten, particularly when the Celebrity dropped in for lunch or dinner.

2. (surfing) To paddle into and take off on a wave another surfer is already riding.
   • 2003, Neal Miyake, The Unwritten Rules of Surfing

     Most beginners are blissfully unaware that dropping in on someone is a cardinal sin.

See also

• drop out
• show up