Innocuous means completely harmless. An innocuous remark, seemingly innocuous, innocuous enough.
It is nearly always used with seemingly or apparently, which tells you what the word is for: an innocuous-looking thing that turned out not to be. The Latin means not harmful, and noxious is the same root with the negative removed.
1adjectiveinnocuousCompletely harmless.
“What seemed an innocuous question upset her far more than I expected.”
innocuous is a quality.
Latin innocuus, in-, not, plus nocuus, harmful, from nocere, to harm. Noxious is a relative.
Proto-Indo-European
*neḱ-
Latin
innocuus — harmless
English, today
innocuous
From Latin innocuus (“harmless”) (therefore, no gemination in + nocuous).
Etymology from Wiktionary, CC BY-SA