MARATHONER Meaning of MARATHONER in English mar ‧ a ‧ thon ‧ er /ˈmærəθɒnə $ -θɑːnər/ BrE AmE ( also ˈmarathon ˌrunner ) noun [countable] someone who runs in a marathon:an Olympic marathoner Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012