cause (a musical instrument) to become out of tune

I'm off to detune my guitar and annoy the neighbours

detuned guitars that sound like they were strung with barbed wire

reduce the performance or efficiency of (a motor vehicle or engine) by adjustment

we've detuned the engines a bit for reliability

a detuned version of a professional rally racer

change the frequency of (an oscillatory system such as a laser) away from a state of resonance

diode lasers can be detuned faster than standard lasers