'hard-edged' originates from English compounding of 'hard' and 'edge'; 'hard' comes from Old English 'heard' (meaning 'firm, solid') and 'edge' comes from Old English 'ecg' (meaning 'blade, border').

'hard' developed from Old English 'heard' through Middle English forms into modern 'hard'; 'edge' developed from Old English 'ecg' into Middle English 'egge/edge'; the compound sense 'hard-edged' (describing something with a hard edge or figuratively severe) arose in Modern English by joining these words.

Initially the elements referred to physical properties ('hard' = firm, 'edge' = blade); over time the compound kept the physical sense ('having a hard/sharp edge') and extended metaphorically to mean 'harsh' or 'uncompromising' in character.