Most searches just talk about Charlie Chaplin, but here's something I found.
Chaplin \ch(ap)-lin\ as a boy's name is of Middle English origin, and the meaning of Chaplin is "secretary".
Hm... I like Wikipedia and found a search result from it.
Chaplin is a surname of English, Ukrainian and Belarusian origin. Surnames of English origin are derived from the occupational name for a clergyman, while Ukrainian and Belarusian uses are derived from chaplya, meaning ‘heron’ or ‘stork’.
I looked up what a clergyman was and I found it was a religious term, as in a priest, a pastor or others. Personally I don't believe in God, Allah etc. so I can't really say that's one I like. Then I looked up stork and heron.
Storks and herons are bird. Hm! That's nice.
To be honest, I don't actually know what it could mean.