'stiffener' originates from English, specifically from the verb 'stiffen', where 'stiff' meant 'rigid' and the suffix '-en' meant 'to make' and the agentive suffix '-er' denotes 'one that makes or causes'.

'stiffener' changed from the verb form 'stiffen' (formed by adding '-en' to Old English 'stíf' meaning 'rigid') and later acquired the agentive noun ending '-er' to form 'stiffener' in modern English.

Initially related to the action 'to make stiff' (stiffen); over time it came to mean the object or device ('one that makes stiff')—i.e., a component that provides stiffness.