By-blow

n. 1. A side or incidental blow; an accidental blow. [ 1913 Webster ]

With their by-blows they did split the very stones in pieces. Bunyan. [ 1913 Webster ]

2. An illegitimate child; a bastard. [ 1913 Webster ]

The Aga speedily . . . brought her [ his disgraced slave ] to court, together with her pretty by-blow, the present Padre Ottomano. Evelyn. [ 1913 Webster ]