Synonyms for Detrimental:

adj.

adverse (adjective)
grievous, difficult, adverse, woeful, unpropitious, catastrophic, antipathetic, unfortunate, inauspicious, miserable, tragic, hard, troublesome, untoward, opposing, calamitous, unfavorable, burdensome, unlucky, distressful, disastrous, unfriendly, perilous.
bad (adjective)
baneful, unfavorable, unsound, irremediable, defective, unsatisfactory, wretched, inadvisable, bad, wrong, displeasing, ill-suited, inferior, black, invalid, unpleasant, inadequate, arrant, poor, vile, faulty.
damaging, disadvantageous (adjective)
baleful, harmful, adverse, disturbing, prejudicial, ill, deleterious, injurious, bad, destructive, evil, unfavorable.
destructive (adjective)
injurious, damaging, devastating, deadly, disastrous, harmful, deleterious, catastrophic, destructive, calamitous.
evil (adjective)
atrocious, destructive, repulsive, sinister, evil, monstrous, heinous, hideous, repugnant, abominable, disgraceful, terrible, bad, foul, damnable, baneful, repellent, sinful, offensive, wicked, revolting, calamitous, loathsome, nefarious, reprehensible.
harmful (adjective)
bad, injurious, unwholesome, deleterious, damaging, baleful, risky, harmful, unhealthy.
unhealthy (adjective)
unwholesome.
useless (adjective)
good-for-nothing, unsuitable, fruitless, nonfunctional, useless, unusable, impractical, unworkable, futile, ineffective, unserviceable, inadequate.

n.

hazardous, unsafe, risky. ill, help. detrimental (noun)
prejudicious, prejudicial, damaging, harmful.

v.

damaging (verb)
study at pernicious, disturbing.

Other synonyms:

ill. Other relevant words:
prejudicious, prejudicial, disturbing, ill.

Usage examples for detrimental

  1. It might be detrimental to his work, on which he set great value, if he angered the old warrior, who was a living source of history. – The Complete Historical Romances of Georg Ebers by Georg Ebers
  2. The cloak of religion too often answers to promote plans detrimental to the peace and happiness of mankind. – Essays on the Constitution of the United States by Paul Leicester Ford
  3. Sir John Marsham, having published the first part of his " Chronology," suffered so much chagrin at the endless controversies which it raised- and some of his critics went so far as to affirm it was designed to be detrimental to revelation- that he burned the second part, which was ready for the press. – Curiosities of Literature, Vol. 1 (of 3) by Isaac D'Israeli