adjective
1.
lacking physical, mental, or moral strength
a weak spirit in a weak body
Synonyms: decrepit, feeble, flimsy, fragile, frail, infirm, insubstantial, puny, unsound, unsubstantial, ||wanky, weakly
Related Word: debilitated, enfeebled, sickly, spindly, weakened; forceless, impotent, impuissant, powerless
Contrasted words: stalwart, stout, sturdy, tenacious, tough; dynamic, energetic, forceful, vigorous
Antonyms: strong
2.
deficient in stability
a love too weak to bear the trials of daily life
Synonyms: dickey, fluctuant, insecure, rootless, shaky, unstable, unsure, vacillating, wavering, wobbly; compare rickety
Related Word: hesitant, irresolute, trimming, uncertain; insubstantial, undependable, unreliable
Contrasted words: certain, secure, solid, stable, sure; dependable, reliable, substantial
Antonyms: strong
3.
Synonyms: implausible , flimsy, improbable, inconceivable, incredible, thick, thin, unbelievable, unconvincing, unsubstantial
4.
not equal to the requirements and demands of a situation
a weak executive
Synonyms: boneless, emasculate, forceless, impotent, inadequate, ineffective, ineffectual, invertebrate, slack-spined, spineless, wan
Related Word: unfit, unqualified, unsuitable; bungling, incompetent, inept
Contrasted words: able, competent, effective, efficient; adequate, fit, qualified, satisfactory, sufficient, suitable; manly, masculine, virile
Antonyms: strong
5.
Synonyms: dilute , diluted, thin, washy, watered-down, waterish, watery
Antonyms: strong