The term 'not essential' can be described by a variety of words, including UNESSENTIAL (11 letters), INESSENTIAL (11 letters), EXTRINSIC (9 letters), NEEDLESS (8 letters), OPTIONAL (8 letters), UNNEEDED (8 letters), EXPENDABLE (10 letters), EXTRANEOUS (10 letters), and SUPERFLUOUS (11 letters). These words all refer to something that is not necessary or required, and can be done without. For example, an EXPENDABLE item is one that can be used up or discarded without affecting the overall outcome. SUPERFLUOUS items are those that are unnecessary or excessive.