drxx - The answer your Lear quote implies is the original answer to 21d which must be entered with the misprint the worplay suggests. Then there's an alteration carried out creating another word, coincidentally not a million miles in meaning from the 5th and 6th letters of the original clue, but this eventual answer doesn't appear in Chambers 2016 print edition. It is in the Oxford Dictionary of English second edition, revised (2005).