An archaic or rare variant meaning to pierce through or penetrate; sometimes used as an alternative to enthrall.
From 'en-' plus 'thrill,' where thrill originally meant to pierce or perforate (from Old English). This is a much older word formation, predating modern usage.
This word is so rare that most modern dictionaries barely mention it, but it shows how English speakers in earlier centuries would combine 'en-' with almost any word they wanted to make it mean 'to cause to be in that state.'
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