bastardly

As a noun bastardry

is (dated) the state of being a bastard (illegitimate child).

As an adjective bastardly is

being born out of marriage.

As adjectives the difference between bastardly and dastardly

is that bastardly is being born out of marriage while dastardly is in the manner of a dastard; marked by cowardice; pusillanimous.

As an adjective bastardly

is being born out of marriage.

As a noun bastardy is

(legal) the condition of being illegitimate, of being born to an unmarried woman or as the fruit of adultery.