
1) Accede to 2) Adequate 3) Allowed 4) Alright 5) Approve 6) Authorize 7) Consent 8) Drivable 9) Endorse 10) Fine 11) Go ahead 12) Indorse 13) Licit 14) Nod 15) Ok 16) Okeh 17) Okey 18) Passable 19) Permission 20) Ratify 21) Reasonable 22) Roger 23) Satisfactory 24) Unhurt 25) Well 26) Yeah 27) Yes
Found on
https://www.crosswordclues.com/clue/okay

1) Acceptable 2) Acceptance word 3) Adequate 4) All right with you 5) All right; satisfactory 6) Alright 7) An endorsement 8) Appprove 9) Approval 10) Approve 11) Approve informally 12) Approve of 13) Approving answer 14) Authorize 15) Casual affirmative 16) Clearance 17) Colloquial affirmative 18) Colloquial word of agreement
Found on
https://www.crosswordclues.com/clue/okay

Okay was slang and is now colloquial English for all right, correct.
Found on
http://www.probertencyclopaedia.com/browse/ZO.HTM

[
adv] - (informal) in a satisfactory or adequate manner
Found on
http://www.webdictionary.co.uk/definition.php?query=okay
O.K. adverb in a satisfactory or adequate manner; `she`ll do okay on her own`; `held up all right under pressure`; (`alright` is a nonstandard variant of `all right`)
Found on
https://www.encyclo.co.uk/local/20974
No exact match found.