[1] : The Collaborative International Dictionary of English v.0.48

bastardly \bas"tardly\, a.
   bastardlike; baseborn; spurious; corrupt. obs. -- adv. in
   the manner of a bastard; spuriously. obs. --shak. donne.
   1913 webster

[2] : WordNet (r) 2.0

bastardly
     adj : born out of wedlock; "the dominions of both rulers passed
           away to their spurious or doubtful offspring"-
           e.a.freeman syn: bastard, misbegot, misbegotten,
            spurious
see also:
bastard misbegot misbegotten spurious 

Bastardly >> B Words
Bastardly, definition of term: Bastardly
bastardly_pag1.html