pencil eraser vs pencil

pencil eraser and pencil both are nouns.

Word	Noun	Adjective	Verb	Adverb
pencil eraser	Yes	No	No	No
pencil	Yes	No	Yes	No

pencil eraser (noun)	pencil (noun)
an eraser made of rubber (or of a synthetic material with properties similar to rubber); commonly mounted at one end of a pencil	a thin cylindrical pointed writing implement; a rod of marking substance encased in wood
	a cosmetic in a long thin stick; designed to be applied to a particular part of the face
	a figure formed by a set of straight lines or light rays meeting at a point
	graphite (or a similar substance) used in such a way as to be a medium of communication

pencil eraser (verb)	pencil (verb)
	write, draw, or trace with a pencil