illegitimate

Not conforming to known principles, or established or accepted rules or standards.

[…] it may be impossible to convince them that the illegitimate power which they obtain, by degrading themselves, is a curse […]

The so-called interstellar space […] has not the properties of ordinary space. It will not conduct sound, nor can a human being move through it. It is therefore illegitimate to measure it in miles.

Not in accordance with the law.

[…] if things went on at this rate it would be doubtful soon whether ever again he would be able to win another election by methods legitimate or illegitimate.

Not sanctioned by marriage.

If we credit the scandal of the former [i.e. his enemies], Artaxerxes sprang from the illegitimate commerce of a tanner’s wife with a common soldier.

His illegitimate birth deprived him of the influence of a father until perhaps his fifth year […]

Not sanctioned by marriage.

an illegitimate child

I am a bastard begot, bastard instructed, bastard in mind, bastard in valour, in every thing illegitimate.

Not sanctioned by marriage.

She had only to collect her memories, which proved to her that “anybody” regarded the illegitimate children as more rightfully to be looked shy on and deprived of social advantages than illegitimate fathers.

I heard last night that a what-do-you-call it?—claimant?—has arrived who says Pat Wayne is his illegitimate father.

A person born to unmarried parents.

Her father and mine was a shameless man and of all his illegitimates I am the most unfortunate and poverty stricken.

To make illegitimate.