noun

1. a person born of parents not married to each other; illegitimate child
2. anything spurious, inferior, or varying from standard
3. Slang a person regarded with contempt, hatred, pity, resentment, etc. or, sometimes, with playful affection: a vulgar usage

Etymology: ME < OFr < bast- (also in fils de bast) (< ? Goth bansts, barn) + -ard, -ard: hence, one conceived in a barn

adjective

1. of illegitimate birth or of uncertain origin
2. of a size or shape that differs from the normal or standard
3. that is not truly the designated thing but that closely resembles it gneiss is called bastard granite
4. not genuine; sham; inferior