Adjectives

(a)unplannedwithout apparent forethought or prompting or planning“an unplanned economy”, “accepts an unplanned order”, “an unplanned pregnancy”, “unplanned remarks”
(s)unintentional, unplanned, unwittingnot done with purpose or intent“an unintentional pun”, “the offense was unintentional”, “an unwitting mistake may be overlooked”