Shannin \sh(an)-nin\ as a girl's name is a variant of Shannon (Gaelic), and the meaning of Shannin is "old, ancient".
The baby name Shannin sounds like Shannen and Shannan. Other similar baby names are Shanti, Shannel, Shannae, Shanie, Shani, Shandon, Shandi, Shannah, Shanna, Shania, Shannea, Shandie, Shanit, Shannice, Shanon, Sharrin, Shawni, Shaunie and Shawnie.