thew

n.

1. A well-developed sinew or muscle.
2. Muscular power or strength. Often used in the plural.

[Middle English, individual habit, virtue, strength (sense influenced by SINEW), from Old English thēaw, a custom, habit.]

thewy thew'y adj.

noun

The state or quality of being physically strong. brawn, might, muscle, potence, potency, power, powerfulness, puissance, sinew, strength. See strong/weak.

IN BRIEF: Well-developed muscles; Strength; Vitality.