The term SCRUB HARD can be summarized by the crossword solution SCOUR, which is a five-letter word. Scouring is the process of cleaning a surface with an abrasive material, such as a brush or cloth, to remove dirt, grime, and other substances. It is often used in household cleaning, such as scrubbing floors, sinks, and countertops. Scrubbing hard is a more vigorous form of scouring, which requires more effort and energy to achieve a deeper clean.