'asmear' is formed in English from the prefix 'a-' (meaning 'on' or 'in a state of') attached to the verb 'smear', creating a variant meaning 'to smear' or 'be smeared' (Early Modern English/18th century usage).

'asmear' developed as a prefixed variant of Middle English 'smeren'/'smeren' (to smear), which itself comes from Old English 'smerian' (to anoint, smear). Over time the prefixed form 'a-' + 'smear' produced 'asmear' in earlier English texts and dialects, though the simple root 'smear' remained dominant.

Initially the elements meant 'a-' (on/in a state) + 'to rub or anoint', producing senses of applying or being covered by a substance; over time usage narrowed and 'asmear' became rare/archaic while 'smear' remained in common use with basically the same core meaning of 'spread or daub a substance'.