The Collaborative International Dictionary of English v.0.48:
Baseborn \Base"born`\, a. 1. Born out of wedlock. --Gay. [1913 Webster] 2. Born of low parentage. [1913 Webster] 3. Vile; mean. "Thy baseborn heart." --Shak. [1913 Webster]WordNet (r) 3.0 (2006):
baseborn adj 1: of low birth or station (`base' is archaic in this sense); "baseborn wretches with dirty faces"; "of humble (or lowly) birth" [syn: base, baseborn, humble, lowly] 2: illegitimate [syn: base, baseborn]