real tennis vs royal tennis

real tennis and royal tennis both are nouns.

Word	Noun	Adjective	Verb	Adverb
real tennis	Yes	No	No	No
royal tennis	Yes	No	No	No

As nouns, real tennis and royal tennis are synonyms defined as:

real tennis and royal tennis: an ancient form of tennis played in a four-walled court

Other synonyms of real tennis include court tennis.

real tennis (noun)	royal tennis (noun)
an ancient form of tennis played in a four-walled court	an ancient form of tennis played in a four-walled court