King-size beats regal (5)
I believe the answer is:
large
'king-size' is the definition.
(similar in meaning)
'beats regal' is the wordplay.
'beats' indicates an anagram.
'regal' is an anagram of 'LARGE'.
(Other definitions for large that I've seen before include "Wide-ranging" , "Generous" , "Gross" , "Of considerable size or extent" , "Big, outsize" .)