Mid 17th century; earliest use found in Thomas Fuller (1607/8–1661), Church of England clergyman. From ricket, variant (in compounds and derivatives) of rickets + -ish.
Definition of ricketish in US English:
ricketish
adjectiveˈrɪkɪtɪʃ
rare
Affected with rickets; rickety.
Origin
Mid 17th century; earliest use found in Thomas Fuller (1607/8–1661), Church of England clergyman. From ricket, variant (in compounds and derivatives) of rickets + -ish.