Unwelcome person

[Ben Jamin]

Is there a single word in English that denotes (in a scornful manner) a person that is not welcome to a group or local society, but tries to join in?
Note: I am not thinking about an intruder, which I think involves an illegal or forced entry, which is not a case here.

 

[sdgraham]

Indeed. Try:

Collins Concise English Dictionary © HarperCollins Publishers::

interloper /ˈɪntəˌləʊpə/n

• an intruder
• a person who introduces himself into professional or social circles where he does not belong
• a person who interferes in matters that are not his concern

 

[DonnyB]

How about "interloper", defined in Oxford Dictionaries Online as: A person who becomes involved in a place or situation where they are not wanted or are considered not to belong.?

 

[Ben Jamin]

Thank you for your response!

Is there another word, more colloquial or even slangy?

 

[cyberpedant]

I frequently see the word "troll" used with more-or-less your desired meaning in fora and chat rooms: "In Internet slang, a troll is a person who sows discord on the Internet by starting arguments or upsetting people, by posting inflammatory, extraneous, or off-topic ...."

 

[DonnyB]

It's used more for parties than groups or societies, but there's "gatecrasher"