(n. & interj.) A sound like a half-formed whistle, expressing astonishment, scorn, or dislike.
(v. i.) To whistle with a shrill pipe, like a plover.
Example Sentences:
(1) @HillaryClinton after Trump's comment about her temperament: "Whew!
(2) Whew, OK!” she said when he was through, smiling.
(3) But his best line was: “Hillary’s got experience, but it’s bad experience.” Clinton’s best line (apart from “Whew, OK!”): “I think Donald just criticized me for preparing for this debate.