wing nut 
noun
1A nut with a pair of projections for the fingers to turn it on a screw.A typical Lancashire-pattern wing nut on the heavy screw tightens the blade....
- The lid is held securely in place by a large wing nut and washer for easy installation or removal - a thoughtful, user friendly touch on the part of RCBS ' design team.
- The tension on the spring can be adjusted using a wing nut so it can grip the line tightly or loosely, whatever the fishing situation demands.
2An Asian tree of the walnut family, with a deeply fissured trunk, compound leaves, and characteristic broad-winged nutlets.
- Genus Pterocarya, family Juglandaceae.
3 (wingnut) US informal A mad or crazy person: some wingnut down in Finance...
- Back then, the wing nut who hit Grogan probably was flagged only for unnecessary roughness.
- Better keep your heads down, little wingnuts.
- I had to go back through my text and remove words like "wingnuts" from my discussion.
3.1A person with extreme, typically right-wing, views: McCarthyite wingnuts...
- I guess she thinks attacking him for being uppity will head off her wingnut primary opponent.
- He's clearly trying to curry favor with the wingnuts.
- For the first time ever, the wingnuts went mainstream.