Antonyms for weak

all:

strong.

cowardly:

determined.

deficient, feeble:

competent, effective, adequate, enough.

faint, soft:

solid, happy, rich.

not strong:

concentrated, noisy, loud, healthy, confident, thick, stable, able, firm, unshaky, potent, certain, bold, sure, protected, capable, secure, unbreakable, safe, guarded, unwavering, strong, active, hearty, fit, sufficient, definite, powerful, brave, steady.

noun:

credible, athletic, demonstrated, righteous, brilliant, wise, able, top, fresh, moral, organized, imperceptible, conspicuous, strapping, competent, principled, validated, tyrannical, confirmed, senior, enlightened, virtuous, bright, upright, clear, Vitalized, ethical, husky, authoritarian, evaporated, dictatorial, magisterial, recovering, skilled, sane, dominant, corroborated, plausible, resolute, invigorated, ordered, infallible, autocratic, condensed, smart, stressed, accented, capable, substantiated, sensible, undiluted, high-level, rugged, certain, nonhuman, unperceivable, major, mettlesome, efficient, despotic, sure, true, daring, right, Backboned, irregular, up, established.