rubberneck vs spectator

rubberneck and spectator both are nouns.

Word	Noun	Adjective	Verb	Adverb
rubberneck	Yes	No	Yes	No
spectator	Yes	No	No	No

As nouns, spectator is a hypernym of rubberneck; that is, spectator is a word with a broader meaning than rubberneck:

rubberneck: a person who stares inquisitively
spectator: a close observer; someone who looks at something (such as an exhibition of some kind)

Other hypernyms of rubberneck include looker, viewer, watcher, witness.

rubberneck (noun)	spectator (noun)
a person who stares inquisitively	a woman's pump with medium heel; usually in contrasting colors for toe and heel
a tourist who is visiting sights of interest	a close observer; someone who looks at something (such as an exhibition of some kind)

rubberneck (verb)	spectator (verb)
strain to watch; stare curiously