The Collaborative International Dictionary of English v.0.48:
Thew \Thew\ (th[=u]), n.
Note: [Chiefly used in the plural Thews (th[=u]z).] [OE.
thew, [thorn]eau, manner, habit, strength, AS.
[thorn]e['a]w manner, habit (cf. [thorn][=y]wan to
drive); akin to OS. thau custom, habit, OHG. dou.
1. Manner; custom; habit; form of behavior; qualities of
mind; disposition; specifically, good qualities; virtues.
For her great light
Of sapience, and for her thews clear. --Chaucer.
Evil speeches destroy good thews. --Wyclif (1
Cor. xv. 33).
To be upbrought in gentle thews and martial might.
2. Muscle or strength; nerve; brawn; sinew. --Shak.
And I myself, who sat apart
And watched them, waxed in every limb;
I felt the thews of Anakim,
The pules of a Titan's heart. --Tennyson.