Thewy is an English adjective that denotes muscularity and strength. Antonyms of thewy, on the other hand, describe a lack of physical strength and power. Weak, frail, delicate, feeble, and floppy are opposites of thewy. These words suggest physical weakness and lack of stamina. Feeble, flabby and floppy even convey a sense of limpness or a lack of resilience. However, antonyms of thewy can also describe other qualities beyond physical strength, including emotional fragility or intellectual incapacity. Some antonyms of thewy within this context may include timid, vacillating, indecisive, and gullible.