different between imparasyllabic vs imparisyllabic

English

imparasyllabic

From Latin impar (“unequal”) + syllabic.

imparisyllabic (not comparable)

Not having the same number of syllables in all its inflections (especially of Greek or Latin nouns); for example, the Latin word pars, which has the genitive form partis.

imparisyllabic (plural imparisyllabics)

An imparisyllabic noun.
- 1974 (revised 1989), Peter Rickard, A History of the French Language, Routledge 2002, pp. 50-1:
  An adjectival type corresponding phonetically to the masculine third declension imparisyllabics is represented by some O.F. survivals of Latin comparative forms

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