nonchalant
‘seeming to be coolly unconcerned or indifferent’
Lexical development traced from the Tamil root:
F. nonchalant ‘careless, indifferent’ < nonchaloir ‘be indifferent to, have no concern for’ < A.F. noun- < O.F. non- < Lat. non ‘not, by no means, not at all, not a’ < O.Lat. noenum ‘not one’ < ne oinom + oi-no- ‘one, unique’ + chaloir ‘have concern for’ < nawn < ne- < Tamil al