Innocuous

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late 16th century: from Latin innocuus, from in- ‘not’ + nocuus ‘injurious’ (see nocuous).

wiktionary

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From Latin innocuus(“harmless”).

etymonline

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innocuous (adj.)

"harmless, producing no ill effect, incapable of harm or mischief,"

1590s, from Latin innocuus "harmless; innocent; inoffensive," from in- "not" (see in- (1)) + nocuus "hurtful," from root of nocere "to injure, harm," from *nok-s-, suffixed form of PIE root *nek- (1) "death." Related: Innocuously; innocuousness.