A rare or obsolete term meaning to degrade or reduce to a base or illegitimate status; possibly to bastardize.
From 'a-' (to) + 'bastard' (an illegitimate child, or something of inferior quality). This appears to be a very old English formation from the 14th-16th centuries, now essentially extinct.
This word is a linguistic fossil—it's so obscure that it probably doesn't appear in any modern usage, yet it shows how English-speakers of centuries past literally 'verbed' the noun 'bastard' to express degradation or loss of legitimacy.
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