Where does “Cly” come from?

Cly (Navajo) comes from Navajo tłʼaaí, from Navajo nishtłʼa — to be left-handed.

Ancestry of “Cly”, step by step

Step	Language	Word	Meaning
1	Navajo	tłʼaaí	lefty, left-handed one
2	Navajo	nishtłʼa	to be left-handed

Cly — Etymology, Origin & Word History | Etymology Explorer