I don't have 14 myself yet. 24 is a hidden word that, obviously, starts with "M". It's not in Chambers but it's in ODE: www . oxforddictionaries . com
It's also worth considering getting Chambers and ODE from Wordweb: wordweb . com as they will help tremendously with this sort of puzzle.
Please note that I do not intend the above link to be viewed as advertising as I have no affiliation with Wordweb.