'asteer' originates from Middle English, ultimately from Old English elements, with the prefix 'a-' (on, in) combined with a root related to 'stir' meaning 'move'.

'asteer' developed as a variant spelling of Middle English 'astir' and corresponds to modern English 'astir', retaining the sense of being 'in motion'.

Initially it meant 'on/in motion' or 'stirred up'; over time it has remained close to the current meaning of 'in motion, active, or agitated', though the spelling 'asteer' became rare or archaic.