ETYMOLOGY
from flatter (vb.) + cap
EXAMPLE
“… He’s struggling to learn a lot of new things, but I also think he’s trying to do whatever he can to get on with the men.
I’ve seen him behaving like a flattercap, all yes sir, no sir, with a seaman named Brian Blount. …”
From: Trouble on the Voyage : The Strange and Dangerous Voyage of the Henrietta Maria
By Bob Barton, 2010
Lexicophilia 