mustachio noun 1verb 1forms 4 noun1 •A mustache, especially a large or lush one.Dompierre twirled his mustachios in relieved approval. — 1914 verb1 •To adorn with a mustachio, or something that resembles a mustachio.We kissed beside the river, we kissed behind her sisters' backs, we kissed with the crema of a freshly made coffee still mustachioing our lips. — 2009 formsmustachioed · moustachioed · mustachioing · mustachios