wax figure vs simulacrum

wax figure and simulacrum both are nouns.

Word	Noun	Adjective	Verb	Adverb
wax figure	Yes	No	No	No
simulacrum	Yes	No	No	No

As nouns, simulacrum is a hypernym of wax figure; that is, simulacrum is a word with a broader meaning than wax figure:

wax figure: an effigy (usually of a famous person) made of wax
simulacrum: a representation of a person (especially in the form of sculpture)

Other hypernyms of wax figure include effigy, image.

wax figure (noun)	simulacrum (noun)
an effigy (usually of a famous person) made of wax	a representation of a person (especially in the form of sculpture)
	an insubstantial or vague semblance