To present participles which come from intransitive verbs, or are themselves employed as adjectives, to mark the absence of the activity, disposition, or condition implied by the participle;

lacking protection or defense

lacking protection or a guard; "an unguarded gate"; "his unguarded queen was open to attack"

Camellia Show term for a plant grown in the open as opposed to in a greenhouse etc.

A property located in an area not regularly serviced by a fire department.