regal vs royal

regal is not a noun while royal is a noun.

Word	Noun	Adjective	Verb	Adverb
regal	No	Yes	No	No
royal	Yes	Yes	No	No

As adjectives, regal and royal are synonyms defined as:

Other synonyms of regal include imperial, majestic, purple.

regal (noun)	royal (noun)
	stag with antlers of 12 or more branches
	a sail set next above the topgallant on a royal mast

regal (adjective)	royal (adjective)
belonging to or befitting a supreme ruler	of or relating to or indicative of or issued or performed by a king or queen or other monarch
	established or chartered or authorized by royalty
	invested with royal power as symbolized by a crown
	being of the rank of a monarch
	belonging to or befitting a supreme ruler