This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
駵 combines 馬 (horse) with 丣, but the exact historical development is uncertain. It may be a variant form related to a horse with a particular coat color, but the component relationship is not clearly established.
A horse 馬 with an unusual right side 丣. Since the meaning is unclear, picture a mysterious, rare horse whose name has been lost.
For リュウ, imagine a rare horse named Ryuu (like 'dragon' 竜) with a flowing mane: Ryuu -> リュウ, and the horse remains mysterious.