common-law marriage vs wedlock

common-law marriage and wedlock both are nouns.

Word	Noun	Adjective	Verb	Adverb
common-law marriage	Yes	No	No	No
wedlock	Yes	No	No	No

As nouns, wedlock is a hypernym of common-law marriage; that is, wedlock is a word with a broader meaning than common-law marriage:

common-law marriage: a marriage relationship created by agreement and cohabitation rather than by ceremony
wedlock: the state of being a married couple voluntarily joined for life (or until divorce)

Other hypernyms of common-law marriage include marriage, matrimony, spousal relationship, union.

common-law marriage (noun)	wedlock (noun)
a marriage relationship created by agreement and cohabitation rather than by ceremony	the state of being a married couple voluntarily joined for life (or until divorce)