desuetude

From the French désuétude, from the Latin dēsuētūdo (“disuse”).

• (UK) IPA^(key): /ˈdɛswɪtjuːd/, /dɪˈsjuːɪtjuːd/
• (US) IPA^(key): /dəˈsuːəˌtuːd/

desuetude (countable and uncountable, plural desuetudes)

1. Disuse, obsolescence (for example, the state of a custom that is no longer observed nor practised).
   • 1819, Sir Walter Scott, Bride of Lammermoor

     […] we of the house of Ravenswood do our endeavour in keeping up, by all just and lawful exertion of our baronial authority, that due and fitting connexion betwixt superior and vassal, which is in some danger of falling into desuetude, owing to the general license and misrule of these present unhappy times.