&quot;coach&quot; is already the correct noun for someone who coaches; no &quot;er&quot; 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 &quot;musicoach&quot; is already taken as a name, that doesn&#x27;t make &quot;musicoacher&quot; viable. Just like you wouldn&#x27;t name your presentation software &quot;Powerpointer&quot;.)<p>Don&#x27;t be a goofball(er?) when naming.<p>---<p>! oxforddictionaries.com does list &quot;coacher&quot; as an Australian word denoting &quot;A docile cow or bullock used as a decoy to attract wild cattle.&quot;