Sentence:  ‘We have just been overtaken by a M.A.M.I.L.' Karen pointed to the cyclist that was now far in the distance. ‘What is a <WSD>MAMIL</WSD>?' ‘It's a Middle Aged Man In Lycra. That is what happens to lots of middle aged men, they decide to take up cycling and wear lycra, which is not the most fetching look on a middle aged man.' 
Meaning of the word marked with <WSD> tags:  (nodot=1): a previously non-athletic man, between 35 and 50, who has taken up cycling seriously for health and/or social reasons.