What is Sybil?
1.
A Sybil, named after the famous psychiatric case of Shirley Mason who reportedly had 16 personalities, and popularized by the book and movie "Sybil" is somebody who acts moody and irregularly. In a self-description, it may refer to a feeling of being "not quite oneself".
Just an hour ago, she seemed fine, now she's lost her temper again. She's a real Sybil.
See
2.
she stole the man of my dreams
Sybil stole him from me.
