still life vs painting

still life and painting both are nouns.

Word	Noun	Adjective	Verb	Adverb
still life	Yes	No	No	No
painting	Yes	No	No	No

As nouns, painting is a hypernym of still life; that is, painting is a word with a broader meaning than still life:

still life: a painting of inanimate objects such as fruit or flowers
painting: graphic art consisting of an artistic composition made by applying paints to a surface

Other hypernyms of still life include picture.

still life (noun)	painting (noun)
a painting of inanimate objects such as fruit or flowers	creating a picture with paints
	the occupation of a house painter
	the act of applying paint to a surface
	graphic art consisting of an artistic composition made by applying paints to a surface