UNPREMEDITATED

adj. unprepared, unplanned, unarranged, uncontrived, unstudied, coincidental, spontaneous, spur-of-the-moment, last-minute, impromptu, extemporaneous or extemporary, extempore, ad lib, offhand, casual, impulsive, natural, involuntary, automatic, unconscious, Colloq off the cuff I had no inkling of her plans, so my running into her was entirely unpremeditated Her immediate, unpremeditated reaction was to run away.