Up in the air

If something, such as a plan or a decision, is up in the air, it has not been decided or settled yet
   Example: I can't give you a definite answer yet; the project is still up in the air

Ugly as sin

This expression is used to refer to people or things that are considered to be very unattractive
   Example:  Have you seen the new neighbor’s dog? It's as ugly as sin

Under your thumb

If someone is under your thumb, they are completely under your control or influence
   Example: Nobody ever protests.  He has the whole group under his thumb

Voice in the wilderness

If you are the only person expressing a warning or an opinion on a matter which is ignored by most others, you are a voice in the wilderness
   Example: For many years she was a voice in the wilderness protesting against child labor

Vote with one's feet

If you vote with your feet, you show your dislike or disapproval of something by leaving
  Example: If the conference is boring, people will probably vote with their feet

Vanish into thin air

If something vanishes into thin air, it disappears completely in a mysterious way
  Example: The diamonds vanished into thin air - nobody knows what happened to them