drop in|drop イディオム
drop in|drop
v. To make a short or unplanned visit; pay a call.

Often used with "on".
We were just sitting down to dinner when Uncle Willie dropped in. The Smiths dropped in on some old friends on their vacation trip to New York. Synonym: DROP BY, RUN IN
2.
drop in|drop
v. To accomplish a abbreviate or adventitious visit; pay a call.

Often acclimated with "on".
We were aloof sitting down to banquet back Uncle Willie alone in. The Smiths alone in on some old accompany on their vacation cruise to New York. Synonym: DROP BY, RUN IN
2. Dictionary