Innocuous comes from Latin innocuus ('harmless'), from in- ('not') + nocuus ('harmful'), from nocere ('to harm'). The historical trail runs through Latin in-, Latin nocere and Proto-Indo-European *nek-. Morphologically, the surface form is analyzable into prefixes, suffixes, compounds, or participial endings that carry part of the history. In modern use it means not harmful or offensive; harmless. Derived formations include innocuously, innocuousness; related forms include noxious, nocent, innocent, nocuous.