Meaning

adjective inclined to shake as from weakness or defect

adjective affected with, suffering from, or characteristic of rickets

adjective lacking bodily or muscular strength or vitality

originFrom dialectal ricket (“unstable, rickety”) + -y, and/or ricket (“to move noisily and in a reckless way”) + -y. Alternatively, and perhaps less likely, from rickets + -y.

Etymology from Wiktionary, CC BY-SA 3.0