1. Occurring without motivation or provocation
   "motiveless malignity"
   - unprovoked, wanton

See also: unmotivated

• unsupervised
• unsupportable
• unsupported
• unsupportive
• unsuppressed
• unsure
• unsurmountable
• unsurpassable
• unsurpassed
• unsurprised
• unsurprising
• unsusceptibility
• unsusceptible
• unsuspected
• unsuspecting
• unsuspectingly
• unsuspicious
• unsustainable
• unswayed
• unsweet
• unsweetened
• unswept
• unswerving
• unswervingly
• unsworn