semen vs cum

semen and cum both are nouns.

Word	Noun	Adjective	Verb	Adverb
semen	Yes	No	No	No
cum	Yes	No	No	No

As nouns, semen and cum are synonyms defined as:

semen and cum: the thick white fluid containing spermatozoa that is ejaculated by the male genital tract

Other synonyms of semen include come, ejaculate, seed, seminal fluid.

semen (noun)	cum (noun)
the thick white fluid containing spermatozoa that is ejaculated by the male genital tract	the thick white fluid containing spermatozoa that is ejaculated by the male genital tract