bastard A child born out of wedlock: an illegitimate child. At common law a bastard has no parents and cannot take property as an heir-at-law or next-of-kin through them. But he can found a family of his own. He can leave real property by will (Law of Property Act 1925 (UK) ,s. 178). Upon the making of an affiliation order, the putative father becomes liable to contribute to the support of his bastard child, of which normally the mother has the custody with the liability to maintain the child.