not firmly or solidly positioned; "climbing carefully up the unsteady ladder"; "an unfirm stance"

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 having a steady rhythm; "an arrhythmic heartbeat"

subject to change or variation especially in behavior; "her unsteady walk"; "his hand was unsteady as he poured the wine"; "an unsteady voice"