Disagree, disappear, disapprove, disconnect, undo, undress, unfasten, unpack, untie.
Disability, disagrement, disadvantage, disapproval, unemployement.
Unbelievable, unconscious, uncomfortable, incorrect, independent, unexpected, unfriendly, unhappy, dishonest, illiterate, unnecessary, impatient, impolite, unpleasant, impossible, irregular, irresponsible.