'asthenia' originates from Greek, specifically the word 'asthēnia', where 'a-' meant 'without' and 'sthenos' meant 'strength'.

'asthenia' changed from the Greek word 'asthēnia' into Late Latin/medical Latin as 'asthenia' and eventually entered modern English as 'asthenia'.

Initially, it meant 'lack of strength'; over time it has remained largely the same but has become a specialized medical term referring to clinical weakness or debility.