In obsolete terms the difference between wedlock and bastard
is that
wedlock is a wife; a married woman while
bastard is to bastardize.
As nouns the difference between wedlock and bastard
is that
wedlock is the state of being married; matrimony while
bastard is a person who was born out of wedlock, and hence often considered an illegitimate descendant.
As an adjective bastard is
of or like a bastard (illegitimate human descendant.
As an interjection bastard is
exclamation of strong dismay or strong sense of being upset.
As a verb bastard is
to bastardize.