The state or quality of being inadvertent; inadvertency; heedlessness; carelessness; negligence. / An effect or result of inattention; an oversight or mistake from negligence.

(rare, obsolete) At a lower level. / (chiefly colloquial) In an inferior or inadequate manner; insufficiently (chiefly in opposition to overly).

A value on the Richter scale

Capable of being proved or clearly brought to light; demonstrable.