The story
From 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 4.0.
rickety
Today it means: Of an object: not strong or sturdy, as because of poor construction or upkeep; not safe or secure. Full definition →