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

underbred \un"derbred`\, a.
   not thoroughly bred; ill-bred; as, an underbred fellow.
   --goldsmith.
   1913 webster

[2] : WordNet (r) 2.0

underbred
     adj 1: of persons lacking in refinement or grace syn: ill-bred,
             bounderish, lowbred, rude, yokelish
     2: of inferior or mixed breed; "a cur dog"; "an underbred dog"
see also:
ill-bred bounderish lowbred rude yokelish 

Underbred >> U Words
Underbred, definition of term: Underbred
underbred_pag1.html