A archaic or poetic term meaning in a state of staring or fixed gaze.
From 'a-' prefix plus 'stare.' The 'a-' prefix in Middle English often indicated a state or condition of being, so 'astare' meant being in the condition of staring.
Poets loved this 'a-' prefix because it was compact—instead of writing 'in a state of staring' they could just write 'astare,' making their verses fit the meter perfectly.
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