Source : Webster's Revised Unabridged Dictionary (1913)

Inflectional \In*flec"tion*al\, a.
   Of or pertaining to inflection; having, or characterized by,
   inflection. --Max M["u]ller.

Source : WordNet®

inflectional
     adj 1: characterized by inflections indicating grammatical
            distinctions; "inflectional morphology is used to
            indicate number and case and tense and person etc."
            [ant: {derivational}]
     2: expressing grammatical relations by means of affixes or
        changes in vowels or consonants