unpleasant
incorrect
incomplete, unfinished
unintentional, mistaken, accidental
poorly, deficiently
not
unhealthy, harmful
evil
intensely, extremely, or exceptional
Greater than normal quantity or importance, as in ultrasecret.
Excessively, to an extreme, as in ultramicroscopic, ultra-careful.
Beyond, outside of, as in ultrasonic.
Beyond, on the far side of, as in ultraviolet.