Desuetude is a noun that means discontinuance from use or exercise.
Our word of the day is a distant relative of the Latin verb suescere (sue ay SHARE ay) meaning ‘to accustom.’ With the prefix DE — which means ‘away’ — the word later evolved to mean ‘a state of not being used.’ Desuetude is a synonym of disuse, but its more ‘old world’ sound may make it a more appropriate word when you need something more sentimental. For example:
In my younger days, I rode my bike all the time. But since buying my car a few years ago, my reliable old 10-speed has fallen into desuetude.