'short-acting' originates from Modern English, specifically the compound of 'short' and the present participle 'acting', where 'short' meant 'not long' and 'act/acting' meant 'to do' or 'produce an effect'.

'short' comes from Old English 'sceort' meaning 'short, brief', while 'act' ultimately traces back to Latin 'agere' ('to do, drive') via Late Latin/Old French forms; the compound 'short-acting' developed in modern English usage by combining these elements to describe duration of action.

Initially the elements separately meant 'not long' ('short') and 'to do/produce effect' ('act'); over time their compound came to specifically denote something that produces an effect for only a short time, especially in medical contexts.