Whatever the federal government’s pluses and minuses, it is usually pretty good at avoiding language that will offend a particular group’s sensibilities. So some Federal Register readers may find it jarring to find two agencies using the term, “mental defective,” in notices set for publication this week. The term, considered useless and derogatory by advocates for the mentally ill, surfaces in a Justice Department filing seeking to clarify definitions of people prohibited from “receiving, possessing, shipping or transporting firearms” under the 1968 Gun Control Act. “The Department recognizes that the term ‘mental defective’ is outdated, but it is included in the statute and…