"coach" is already the correct noun for someone who coaches; no "er" is required. There is no such word(!), and no such word is necessary; it sounds like the spontaneous creation of a non-native English speaker (or a native one under four years old).<p>(If "musicoach" is already taken as a name, that doesn't make "musicoacher" viable. Just like you wouldn't name your presentation software "Powerpointer".)<p>Don't be a goofball(er?) when naming.<p>---<p>! oxforddictionaries.com does list "coacher" as an Australian word denoting "A docile cow or bullock used as a decoy to attract wild cattle."