Synonyms for Nonsyllabic (same or very similar meaning)
WordNet sense 1 (not forming a syllable or the nucleus of a syllable; consisting of a consonant sound accompanied in the same syllable by a vowel sound or consisting of a vowel sound dominated by other vowel sounds in a syllable (as the second vowel in a falling diphthong)):
unsyllabicFrom the ODE community, based on WordNetadd/edit