“+ adjective
Etymology: probably from Late Latin inconvertibilis, from Latin in- in- (I) + convertibilis changeable — more at convertible
: not capable of being changed into or exchanged for something else
the alchemists were unwilling to accept the inconvertible nature of elemental metals
a. of paper money : not exchangeable on demand for specie
b. of a currency : not exchangeable for a foreign currency
• in·con·vert·ibly -əblē, -li adverb