WordWeb Online

1. Not brought to a conclusion; subject to further thought
   "our position on this bill is still undecided";
   - open, undetermined, unresolved
    
2. Characterized by indecision
   "too many voters still declare they are undecided";
   - on the fence
    
3. Not yet having made a commitment
   "undecided voters"

1. A voter (etc.) who has not yet come to a decision

Derived forms: undecideds

See also: dithery [informal], free-floating [informal], indecisive, uncommitted, unsettled

Encyclopedia: Undecided