Concerning or involving calamity, disastrous.
‘The city was struck by a calamitous cyclone.’;
Harmful often in a subtle or unexpected way.
‘deleterious effects’; ‘deleterious to someone's health’;
Suffering calamity; wretched; miserable.
‘Ten thousands of calamitous persons.’;
Hurtful; noxious; destructive; pernicious; as, a deleterious plant or quality; a deleterious example.
Producing, or attended with distress and misery; making wretched; wretched; unhappy.
harmful to living things;
‘deleterious chemical additives’;
(of events) having extremely unfortunate or dire consequences; bringing ruin;
‘the stock market crashed on Black Friday’; ‘a calamitous defeat’; ‘the battle was a disastrous end to a disastrous campaign’; ‘such doctrines, if true, would be absolutely fatal to my theory’; ‘it is fatal to enter any war without the will to win it’; ‘a fateful error’;
causing harm or damage
‘divorce is assumed to have deleterious effects on children’;