Sentence:  In former days every tavern of repute kept such a room for its own select circle, a club, or society, of habitués, who met every evening, for a pipe and a cheerful glass....<WSD>Strangers</WSD> might enter the room, but they were made to feel that they were there on sufferance: they were received with distance and suspicion. 
Meaning of the word marked with <WSD> tags:  A person whom one does not know; a person who is neither a friend nor an acquaintance.