'atwist' originates from the Old English prefix 'a-' (from Old English 'on'/'a', meaning 'on, in') combined with the word 'twist' (from Old English 'twist'/'twistan', meaning 'to turn, wind').

'atwist' appears in Middle English in forms such as 'atwiste' or 'atwisted' formed by the prefix a- + past-participle/adjective of 'twist'; it survived into modern English chiefly as an archaic or literary word 'atwist'.

Initially it meant 'in a twisted or turned state'; over time it retained that core idea but became marked as archaic/literary and acquired the broader sense 'awry' (not as intended).