Satan vs Beelzebub

Satan and Beelzebub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Satan	Yes	No	No	No
Beelzebub	Yes	No	No	No

As nouns, Satan and Beelzebub are synonyms defined as:

Satan and Beelzebub: (Judeo-Christian and Islamic religions) chief spirit of evil and adversary of God; tempter of mankind; master of Hell

Other synonyms of Satan include Devil, Lucifer, Old Nick, Prince of Darkness, the Tempter.

Satan (noun)	Beelzebub (noun)
(Judeo-Christian and Islamic religions) chief spirit of evil and adversary of God; tempter of mankind; master of Hell	(Judeo-Christian and Islamic religions) chief spirit of evil and adversary of God; tempter of mankind; master of Hell