copula vs copulative

copula and copulative both are nouns.

Word	Noun	Adjective	Verb	Adverb
copula	Yes	No	No	No
copulative	Yes	Yes	No	No

As nouns, copula and copulative are synonyms defined as:

copula and copulative: an equating verb (such as `be' or `become') that links the subject with the complement of a sentence

Other synonyms of copula include linking verb.

copula (noun)	copulative (noun)
an equating verb (such as `be' or `become') that links the subject with the complement of a sentence	an equating verb (such as `be' or `become') that links the subject with the complement of a sentence

copula (adjective)	copulative (adjective)
	syntactically connecting sentences or elements of a sentence