sustaining adjective 1noun 1forms 3 adjective1 •That sustains, supports or provides sustenance.[…] eternall life, the end of all our wearisome labours, and all our sustaining hopes. — 1641 noun1 •The process by which something is sustained or upheld.Beginnings are very different from sustainings; the irregular, often violent, and improvised actions of the founder hero must be succeeded by the regular election of leaders according to law. — 2012 formssustainings · more sustaining · most sustaining