Antonyms of adj innocuous

3 senses of innocuous

Sense 1
innocuous (vs. noxious) -- (not injurious to physical or mental health)

noxious (vs. innocuous) -- (injurious to physical or mental health; "noxious chemical wastes"; "noxious ideas")
        => baneful, deadly, pernicious, pestilent -- (exceedingly harmful)
        => corrupting, degrading -- (harmful to the mind or morals; "corrupt judges and their corrupting influence"; "the vicious and degrading cult of violence")
        => vesicatory, vesicant -- (causing blisters)

Sense 2
innocuous, unobjectionable -- (not causing disapproval; "it was an innocuous remark"; "confined himself to innocuous generalities"; "unobjectionable behavior")

INDIRECT (VIA inoffensive) -> offensive -- (unpleasant or disgusting especially to the senses; "offensive odors")

Sense 3
innocent, innocuous -- (lacking intent or capacity to injure; "an innocent prank")

INDIRECT (VIA harmless) -> harmful -- (causing or capable of causing harm; "too much sun is harmful to the skin"; "harmful effects of smoking")

Similarity of adj innocuous

3 senses of innocuous

Sense 1
innocuous (vs. noxious) -- (not injurious to physical or mental health)
       => innoxious -- (having no adverse effect)
          Also See-> harmless#1

Sense 2
innocuous, unobjectionable -- (not causing disapproval; "it was an innocuous remark"; "confined himself to innocuous generalities"; "unobjectionable behavior")
       => inoffensive (vs. offensive) -- (giving no offense; "a quiet inoffensive man"; "a refreshing inoffensive stimulant")

Sense 3
innocent, innocuous -- (lacking intent or capacity to injure; "an innocent prank")
       => harmless (vs. harmful) -- (not causing or capable of causing harm; "harmless bacteria"; "rendered the bomb harmless")