athematic

athematic [ey-thee-mat-ik] ExamplesWord Origin adjective

1. inflected without a thematic vowel.

Origin of athematic First recorded in 1890–95; a-6 + thematic Examples from the Web for athematic Historical Examples of athematic

In the verb the athematic conjugation has disappeared and the distinction of primary and secondary endings is not observed.

Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5

Various

British Dictionary definitions for athematic athematic adjective

1. music not based on themes
2. linguistics (of verbs) having a suffix attached immediately to the stem, without an intervening vowel