conjugation vs union

conjugation and union both are nouns.

Word	Noun	Adjective	Verb	Adverb
conjugation	Yes	No	No	No
union	Yes	Yes	No	No

As nouns, conjugation and union are synonyms defined as:

conjugation and union: the act of pairing a male and female for reproductive purposes

Other synonyms of conjugation include coupling, mating, pairing, sexual union.

As nouns, conjugation and union are synonyms defined as:

Other synonyms of conjugation include jointure, unification, uniting.

As nouns, union is a hypernym of conjugation; that is, union is a word with a broader meaning than conjugation:

Other hypernyms of conjugation include unification.

conjugation (noun)	union (noun)
the act of pairing a male and female for reproductive purposes	the act of making or becoming a single unit
the act of making or becoming a single unit	the act of pairing a male and female for reproductive purposes
a class of verbs having the same inflectional forms	a device on a national flag emblematic of the union of two or more sovereignties (typically in the upper inner corner)
the complete set of inflected forms of a verb	the occurrence of a uniting of separate parts
the inflection of verbs	an organization of employees formed to bargain with the employer
the state of being joined together	a political unit formed from previously independent people or organizations
	a set containing all and only the members of two or more given sets
	healing process involving the growing together of the edges of a wound or the growing together of broken bones
	the state of being joined or united or linked
	the state of being a married couple voluntarily joined for life (or until divorce)

conjugation (adjective)	union (adjective)
	of trade unions