A "natural" child; a child begotten and born out of wedlock; an illegitimate child; one born of an illicit union.
- A child born out of wedlock.
- Something that is of irregular, inferior, or dubious origin.
- Slang A person, especially one who is held to be mean or disagreeable.
- Born of unwed parents; illegitimate.
- Not genuine; spurious: a bastard style of architecture.
- Resembling a known kind or species but not truly such.