Baseborn means born of low or illegitimate birth. A baseborn son, called him baseborn, baseborn and landless.
It is archaic and belongs to historical writing, where the insult carried real legal weight, since illegitimacy barred inheritance. The base in it means low in rank rather than wicked.
1adjectivebasebornBorn of low or illegitimate birth.
“The baseborn son of the king could never inherit the throne.”
baseborn is a state.
Base, in the old sense of low in rank, plus born, from Old French bas, low, from Latin bassus.
From base + born.
Etymology from Wiktionary, CC BY-SA
Practised in A Song of Ice and Fire