twiddler

/ˈtwɪdələr/
noun
  1. A person who twists, turns, or fiddles with something, often idly or nervously.
    • My little brother is a twiddler who can't sit still without playing with something in his hands.
    • The nervous twiddler kept spinning his pen during the meeting.
    • She's a twiddler, always twisting her hair or tapping her fingers.
  2. A device or control used for adjusting or fine-tuning something, such as a knob or dial.
    • The old amplifier had a twiddler for bass and another for treble.
    • The radio's volume twiddler was stuck, so I couldn't turn it down.
    • He adjusted the twiddler on the telescope to sharpen the image.
Synonyms