Capable of endurance; tough; sinewy; as, a wiry frame or constitution.

thin, flexible, and tough.

lean and sinewy

Leaf appearance of a well-twisted, thin, long leaf.

Term applied to well twisted, thin leaf orange pekoe. A good OP has long, very black even sized twisted leaf.

Another term which means well twisted.

Made of wire; like wire; drawn out like wire.