bathing vs vapour bath

bathing and vapour bath both are nouns.

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

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

bathing: the act of washing yourself (or another person)
vapour 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, vapor bath.

bathing (noun)	vapour 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