bathing vs vapor bath

bathing and vapor bath both are nouns.

Word	Noun	Adjective	Verb	Adverb
bathing	Yes	No	No	No
vapor bath	Yes	No	No	No

As nouns, vapor bath is a hyponym of bathing; that is, vapor bath is a word with a more specific, narrower meaning than bathing:

bathing: the act of washing yourself (or another person)
vapor bath: you sweat in a steam room before getting a rubdown and cold shower

Other hyponyms of bathing include shower, shower bath, bath, sponge bath, steam bath, Turkish bath, vapour bath.

bathing (noun)	vapor bath (noun)
immersing the body in water or sunshine	you sweat in a steam room before getting a rubdown and cold shower
the act of washing yourself (or another person)	a room that can be filled with steam in which people bathe; `vapour bath' is a British term