LONE

[adjective] [before noun; not gradable] - without other similar ones; being the only one in a place or situationThe body was discovered in the forest by a lone hunter.Entering the competition as the lone outsider among established players does not worry him in the least.He was a lone voice (= the only person) arguing against a reduction in resources. [before noun]A lone parent/mother/father is one who has children but no partner living with them.A lone wolf is a loner.