'Sustainer' definitions:

Definition of 'sustainer'

From: WordNet
noun
Someone who upholds or maintains; "firm upholders of tradition"; "they are sustainers of the idea of democracy" [syn: upholder, maintainer, sustainer]

Definition of 'Sustainer'

From: GCIDE
  • Sustainer \Sus*tain"er\, n. One who, or that which, sustains. --Waterland. [1913 Webster]