mainspring Synonyms

vital element driving force motivation wellspring wellhead well spring source slipshoe root reason creator cornerstone starting point main ingredient key element fermentation agent headstream fons et origo beginnings babouche baboosh prime mover fountainhead principle primum mobile pantofle fountain fount foundation drive core cause beginning basis base author gavelock ground impetus origin occasioner mule motive linchpin keystone intention inspiration incentive impulse