SNOOP AROUND, SNOOP ROUND, SNOOP ABOUT, DROP IN (1), DROP INTO (1)

snoop around = look around a place trying to find secrets (irritating other people)

examples:

• A man was snooping around our shop this morning. He pretended to be a customer but I had a feeling he wanted to find out about our business.
• If she comes again snooping around, tell her it is not her business what we do in our family. 
• They were snooping around the office and I thought they were tax collectors.
• The manager sometimes comes downstairs to snoop about.
• His secretary 's job is mainly to snoop around the office and report to the boss.
• The inspector came by and started asking questions. He is snooping around to find more about the case.

drop in (on somebody) / (at a place, into a place) = make a short visit (usually without calling first)
examples:

• I dropped in to see Jane yesterday.
• I dropped in at the hospital to see my grandmother.
• My children always drop in on me every weekend.
• Drop in to see me when you are in town.
• I dropped in on Mary on my way to the office.
• Could you drop in at the doctor's and get the prescription for my medicine?
• We dropped into a bar for a beer.
• I dropped into the supermarket for some milk and butter.
• I dropped into the baker's for a loaf of bread.