athematic

From a- + thematic.

• (UK, US) enPR: ăthē-măt'ĭk, IPA^(key): /ˌæθiːˈmætɪk/

athematic (not comparable)

1. (linguistics) Of a root, not having a thematic vowel and thus attaching inflections directly to the root.
   • 2017 -, Mate Kapović, Anna Giacalone Ramat, Paolo Ramat, The Indo-European Languages, →ISBN:

     Celtic tended to thematicize athematic verbs and to generalize a single grade of ablaut, usually the zero grade of the plural:...