void vs null

void and null both are nouns.

Word	Noun	Adjective	Verb	Adverb
void	Yes	Yes	Yes	No
null	Yes	Yes	No	No

As adjectives, void and null are synonyms defined as:

void (noun)	null (noun)
an empty area or space	a quantity of no importance; thing (object:), singular, negative pronoun; pronoun, thing, singular; quantifier: negative existential
the state of nonexistence

void (adjective)	null (adjective)
containing nothing	lacking any legal or binding force
lacking any legal or binding force

void (verb)	null (verb)
excrete or discharge from the body
take away the legal force of or render ineffective
clear (a room, house, place) of occupants or empty or clear (a place or receptacle) of something
declare invalid