beating vs flagellation

beating and flagellation both are nouns.

Word	Noun	Adjective	Verb	Adverb
beating	Yes	No	No	No
flagellation	Yes	No	No	No

As nouns, flagellation is a hyponym of beating; that is, flagellation is a word with a more specific, narrower meaning than beating:

Other hyponyms of beating include flogging, lashing, tanning, whipping.

beating (noun)	flagellation (noun)
the act of inflicting corporal punishment with repeated blows	beating with a whip or strap or rope as a form of punishment
the act of overcoming or outdoing	beating as a source of erotic or religious stimulation