Definition: Detrimental, injurious; the antonym of beneficial.
Usage: The adverb is "deleteriously" and the noun, "deleteriousness." The delightful humor of Ogden Nash hardly bears up to Byron's lines, "'Tis a pity wine should be so deleterious, For tea and coffee leave us much more serious" (Don Juan iv. 52). For Ogden Nash you have to work for, go to our Enigma Puzzle room.
Suggested Usage: Here is the dilemma: repressed feelings can be deleterious to your health but then so being punched by someone you express your true feelings to. Another one of life's thorny problems: A melted chocolate truffle could be deleterious to the other bonbons in your candy dish, so eating it early in its life is the best policy.
Etymology: From Greek deleterios from deleisthai "to harm" via Vulgar Latin deleterius and French délétère (Italian deleterio). –Dr. Language, YourDictionary.com
Chocolate was thought to be deleterious to your health but dark chocolate has been found to be beneficial in small amounts. OOOOHH CHOCOLATE......