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;

Not armed or armored; having no arms or weapons.

Not in a state in which it may be detonated; unable to be detonated; -- used of nuclear and certain other explosive devices, which, as a safety precaution, are stored and transported in a state in which normal triggering mechanisms will not function to cause the device to detonate. The weapon must first be armed by a separate action, and only subsequent to such arming will the weapon be able to detonate.

(used of persons or the military) not having or using arms; "went alone and unarmed"; "unarmed peasants were shot down"; "unarmed vehicles"

Having no hard and sharp projections, as spines, prickles, spurs, claws, etc.

without spines

Without prickles

used of plants or animals; without barbs or stings

Unisexual Flowers