MAMIL

noun2

1. •
   Acronym of middle-aged man in Lycra, a previously non-athletic man, between 35 and 50, who has taken up cycling seriously for health and/or social reasons.

   • Cycling has created the phenomenon of the MAMIL—Middle-Aged Men In Lycra—because it's enjoyable, it's accessible and it's easy to take up. All you need to know is how to ride a bike. — 2019
2. •
   Acronym of middle-aged matron in Lycra, a female equivalent.

noun1

1. •
   Alternative letter-case form of MAMIL.

   • And ladies, if you have a man at home taking an unusual interest in how you shave your legs, you may have a Mamil in the making too. — 2010