This is the 10234th most frequent French word.
inconnu
Unknown.
Here, 'inconnu' functions as an adjective describing the place unknown to tourists.
Ce lieu est inconnu de nombreux touristes.
This place is unknown to many tourists.
In this sentence, 'inconnu' acts as an adjective specifying the unidentified man.
Un homme inconnu lui a offert de l'aide.
An unknown man offered him help.
Here, 'inconnu' is used as a noun referring to something that is not known or understood.