foliage vs fig leaf

foliage and fig leaf both are nouns.

Word	Noun	Adjective	Verb	Adverb
foliage	Yes	No	No	No
fig leaf	Yes	No	No	No

As nouns, fig leaf is a hyponym of foliage; that is, fig leaf is a word with a more specific, narrower meaning than foliage:

foliage: the main organ of photosynthesis and transpiration in higher plants
fig leaf: a leaf from a fig tree

foliage (noun)	fig leaf (noun)
(architecture) leaf-like architectural ornament	a covering consisting of anything intended to conceal something regarded as shameful
the main organ of photosynthesis and transpiration in higher plants	a leaf from a fig tree