It's "ermine." I'm sure you know that. Or at least I think you do.
If not, and you were transcribing it by listening, perhaps this is a "Don't you love arse" thing. I can't imagine anyone ever actually heard it that way, but Sondheim said it was a potential problem. Or it's like "To make two lovers a friend," although even as a child, I knew that was "To make two lovers of friends," but Sondheim talked about this as something he personally misheard.