undeclinable

== English == === Etymology === From un- +‎ declinable. === Adjective === undeclinable (not comparable) Synonym of indeclinable. === Noun === undeclinable (plural undeclinables) Synonym of indeclinable. === Further reading === “indeclinable, undeclinable, nondeclinable, non-declinable”, in Google Books Ngram Viewer.