Definitions of solitary:

• noun:   confinement of a prisoner in isolation from other prisoners

  Example: "He was held in solitary"

• noun:   one who lives in solitude
• adjective:   enjoyed or performed alone

  Example: "Took a solitary walk"

• adjective:   separated from or unfrequented by others; remote or secluded

  Example: "A solitary retreat"

• adjective:   of plants and animals; not growing or living in groups or colonies

  Example: "Solitary bees"

• adjective:   characterized by or preferring solitude in mode of life

  Example: "A man of a solitary disposition"

• adjective:   lacking companions or companionship

  Example: "A solitary traveler"