unhappy (な adj.)

irregular (な adj.)

strange, mysterious (な adj.)

dissatisfied (な adj.)

uneasy, nervous (な adj.)

to be short of, to be lacking

sudden, abrupt, unexpected, unforeseen

indispensable, essential

ominous, sinister, bad luck, ill omen, inauspiciousness

recession, depression, slump

business recession, hard times, depression, gloom, sullenness, cheerlessness

absence

to romp, to gambol, to frolic, to joke, to make fun of, to flirt

incomplete understanding, doubt, question, distrust, suspicion, strangeness, infidelity

dullness, depression, slump, stagnation

irregularity, unseasonableness

bad condition, not to work out (ie a deal), disagreement, break-off, disorder, slump, out of form

suddenly, casually, accidentally, incidentally, unexpectedly, unintentionally

injustice, impropriety, unreasonableness, undeservedness, unfair, invalid

real estate

bad reputation, disgrace, unpopularity

pity, compassion

dissatisfaction, discontent, disapproval, objection, complaint, protest, disagreement

unknown, obscure, indistinct, uncertain, ambiguous, ignorant, lack of wisdom, anonymous, unidentified

badness, delinquent, inferiority, failure

unappetising, unpleasant (taste appearance situation), ugly, unskilful, awkward, bungling, unwise, untime

unlucky, misfortune, bad luck, fate

unclean, dirty, filthy, impure

suspension, interruption, stoppage, tie-up, cessation

un, non, negative prefix