Cilly \ci(l)-ly\ as a girl's name is a variant of Cecilia (Latin, Old Welsh) and Cecily (Latin, Old Welsh), and the meaning of Cilly is "blind; sixth".

The baby name Cilly sounds like Cilla, Cilia, Cili, Cile, Celli, Sally and Zilla. Other similar baby names are Milly, Billy, Cally, Colly, Gilly, Hilly, Jilly, Lilly, Tilly and Willy.