Nose about
Definition 1 of 1
Pro Tip 1/3Curiosity Implication
Indicates a curious or intrusive interest in something, often with a negative tone. 
He's always nosing about in confidential files he shouldn't access.
Pro Tip 2/3Often Informal
Mostly used in casual speech; might be informal for some business or academic situations. 
I caught the new intern nosing about the office.
Pro Tip 3/3Conveys Suspicion
Can imply that the person is being suspicious or distrustful of what's hidden. 
The manager noticed employees nosing about the memo.