onanism vs birth control

onanism and birth control both are nouns.

Word	Noun	Adjective	Verb	Adverb
onanism	Yes	No	No	No
birth control	Yes	No	No	No

As nouns, birth control is a hypernym of onanism; that is, birth control is a word with a broader meaning than onanism:

onanism: a method of birth control in which coitus is initiated but the penis is deliberately withdrawn before ejaculation
birth control: limiting the number of children born

Other hypernyms of onanism include birth prevention, family planning.

onanism (noun)	birth control (noun)
manual stimulation of the genital organs (of yourself or another) for sexual pleasure	limiting the number of children born
a method of birth control in which coitus is initiated but the penis is deliberately withdrawn before ejaculation