What is the abstract noun for harsh?

The noun form of the adjective 'tough' is toughness.

The noun 'toughness' is a concrete noun as a Word for the physical property of a material that enables it to absorb large amounts of energy.

The noun 'toughness' is an abstract noun as a Word for mental and emotional determination and stamina.

Synonyms for the adjective tough:

1) cohesive, durable, firm, hard, inflexible, leathery, resilient, resistant, rigid, rugged, solid, stiff, strong, sturdy, tenacious

2 brawny, fit, hard as nails, hardened, hardy, resilient, seasoned, stalwart, stout, strapping, strong, sturdy, vigorous

3 hard-bitten, pugnacious, rough, ruffianly, ruthless, vicious, violent

4 adamant, callous, exacting, firm, hard, hard-boiled (informal) hard-nosed (informal) inflexible, intractable, merciless, obdurate, obstinate, refractory, resolute, severe, stern, strict, stubborn, unbending, unforgiving, unyielding

5 arduous, baffling, difficult, exacting, exhausting, hard, intractable, irksome, knotty, laborious, perplexing, puzzling, strenuous, thorny, troublesome, uphill