1940s; earliest use found in Budd Schulberg (1914–2009), screenwriter and novelist. Humorous alteration of okey-dokey. Perhaps compare yokel adjective.
Definition of okle-dokle in US English:
okle-dokle
(also ok'l dok'l)
exclamationˌəʊklˈdəʊkl
US humorous
OK.
Origin
1940s; earliest use found in Budd Schulberg (1914–2009), screenwriter and novelist. Humorous alteration of okey-dokey. Perhaps compare yokel [adjective].