Solitary; having no companion. / Isolated or lonely; lacking companionship. / Sole; being the only one of a type. / Situated by itself or by oneself, with no neighbours.

(now rare) The state of being alone; loneliness, solitariness.

Unhappy because of feeling isolated from contact with other people. / (of a place or time) Unfrequented by people; desolate. / (of a person) Without companions; solitary.

(idiomatic) To go alone.

(idiomatic) An individual person who acts on his or her own initiative, without partners, especially one who has sole responsibility for doing something questionable, confidential, or iniquitous.

plural of no-lone zone

plural of lonely-heart

(informal) A person with no friends of the opposite sex who is looking for a spouse or companion

Of a newspaper column: in which people attempt to find friends of the opposite sex.

A hero of westerns who wore a mask. / A solitary, sometimes mysterious or heroic, person.