Not to be confused with the person who literally has a big nose, being a big nose indicates that the person in question is nosy, meddlesome, or intrusive into things that others view as being private. A big nose tends to get too involved in other people’s activities and may also be referred to as a busybody. This term is also frequently applied to investigators, police detectives, or other agency personnel that make it their business to know other people’s business. Someone might say, “The big nose was asking a lot of questions.”
Terms like "big nose" are known as idioms. Idiomatic expressions can be interesting pieces of a language, but they can also sometimes be confusing, especially for people who are not fluent in the particular language in which they are used. “Raining cats and dogs” is an idiom, one that could obviously be very confusing. Clearly, it is an exaggerated descriptive phrase, and not meant to be taken literally in any way.
Being a big nose may also be seen as exaggeration since in literal terms it has nothing to do with the actual size of that particular facial feature. It can be said that such a person leads with his nose, or sticks his nose where it doesn’t belong. Calling someone a big nose is another way of telling that person, “Mind your own business.” While it might not seem very polite to use such terms, it is not polite to invade another person’s privacy either.
A person who snoops or asks too many questions may also be referred to as a "nosy parker." A person can get him or herself into trouble by being too nosy. There are many stories and shows that depict the nosy neighbor getting in over his head with the police or the bad guys, because he or she tried to play amateur detective. Sneaking around or otherwise getting involved in other people’s private affairs without their permission is generally not a good idea.
The term is not just reserved for the sneaky type of nosy person either. It may also be used to describe someone that asks personal questions in front of other people. “That big nose asked me how much money I make per year, in front of everyone at the party!”