38 synonyms for detrimental such as baleful, adverse, and bad. Detrimental is an adjective, and its antonyms are benign and beneficial.
Adverse, bad, baleful, calamitous, cancerous, corrupting, counterproductive, damaging, dangerous, deadly, deleterious, destructive, disastrous, environmentally unfriendly, evil, fatal, harmful, hurtful, ill, inimical, injurious, lethal, malefic, maleficent, malign, malignant, noxious, pernicious, poisonous, prejudicial, prejudicious, ruinous, undesirable, unfavourable, unfortunate, unhealthy, and unwholesome.