babe vs war baby

babe and war baby both are nouns.

Word	Noun	Adjective	Verb	Adverb
babe	Yes	No	No	No
war baby	Yes	No	No	No

As nouns, war baby is a hyponym of babe; that is, war baby is a word with a more specific, narrower meaning than babe:

babe: a very young child (birth to 1 year) who has not yet begun to walk or talk
war baby: conceived or born during war

babe (noun)	war baby (noun)
a very young child (birth to 1 year) who has not yet begun to walk or talk	conceived or born during war