untangle (v.) untangible (adj.) untamed (adj.) untainted (adj.) unsystematic (adj.) unsympathetic (adj.) unswerving (adj.) unsweetened (n.) unswayed (adj.) unsustainable (adj.) unsuspecting (adj.) unsuspected (adj.) unsurpassed (adj.) unsurpassable (adj.) unsurmountable (adj.) unsure (adj.) unsupported (adj.) unsupervised (adj.) unsung (adj.) unsullied (adj.)