The Collaborative International Dictionary
Suppletive
Suppletive \Sup"ple*tive\, Suppletory \Sup"ple*to*ry\, a. [Cf. F. suppl['e]tif, LL. suppletivus, from L. supplere, suppletum, to fill up. See Supply.] Supplying deficiencies; supplementary; as, a suppletory oath.
Wiktionary
suppletive
a. 1 (context grammar English) inflect by substituting an unrelated form (for example, in English, the adjectival forms ''good'', ''better,'' ''best''). 2 Supplying deficiencies; supplementary; suppletory.