Privative

A privative, named from Latin privare 'to deprive',[1] is a particle that negates or inverts the value of the stem of the word.

In Indo-European languages, many privatives are prefixes, but they can also be suffixes, or more independent elements.

In English there are three primary privative prefixes, all cognate from Proto-Indo-European: These all stem from a PIE syllabic nasal privative *n̥-, the zero ablaut grade of the negation *ne, i.e. "n" used as a vowel, as in some English pronunciations of "button".

In North Germanic languages, the -n- has disappeared and Old Norse has ú- (e.g. ú-dáins-akr), which became u- in Danish and Norwegian, o- in Swedish, and ó- in Icelandic.

Since at least the 1920s, there have been calls to stop using inflammable and substitute it exclusively with flammable to avoid the confusion that occurs even by native English-speakers.