drop-in
1 of 2noun
ˈdräp-ˌin 
1
: a casual visit or brief stop
2
: one who drops in : a casual visitor
drop in
2 of 2verb
dropped in; dropping in; drops in
intransitive verb
: to pay an unexpected or casual visit —often used with on
Synonyms
Noun
- caller
- frequenter
- guest
- visitant
- visitor
Verb
- call
- come by
- come over
- drop by
- pop (in)
- run (over)
- run in
- step in
- stop (by or in)
- visit
See all Synonyms & Antonyms 
Example Sentences
Verb drop in any time—we're always home
Word History
First Known Use
Noun
1819, in the meaning defined at sense 1
Verb
circa 1600, in the meaning defined above