non-essential
‘not absolutely necessary’
Lexical development traced from the Tamil root:
non ‘not’ < A.F. noun- < O.F. non- < Lat. non ‘not, by no means, not at all, not a’ < O.Lat. noenum ‘not one’ < ne oinom < ne- ‘not’ + oinom + essential ‘that is such by its essence’ < awn < oi-no- < Tamil oṉṟu