the first-born illegitimate son of parents whose second son was legitimate.
- Bastard cut
adjective (mechanical engineering) (of a file) having medium teeth; intermediate between a coarse cut and a fine cut
- Bastard file
a file of the commercial grade of coarseness between coarse and second-cut.
- Bastard indigo
a bushy shrub, Amorpha fruticosa, of the legume family, native to North America, having elongated clusters of dull purplish or bluish flowers.
- Bastard mahogany
an Australian tree, Eucalyptus botryoides, of the myrtle family, having lance-shaped leaves and furrowed bark.