supply-side adjective 1supply side noun 1forms 3 adjective1 •Regarding or promoting the supply side of the economy.Brown told her that she sounded very supply-side, but what about that memo to Muskie, which had recently surfaced, denouncing supply-siders as a “right-wing claque”? — 1984 supply side noun1 •In a market trade, the side where the supply comes from. formssupply sides · more supply-side · most supply-side