Gadfly

Querulant

(person or thing that irritates or instigates)

Querulant

(person who upsets the status quo by posing novel or upsetting questions, or attempts to stimulate innovation by being an irritant)

Quälgeist

(person or thing that irritates or instigates)

Quälgeist

(person who upsets the status quo by posing novel or upsetting questions, or attempts to stimulate innovation by being an irritant)

Störenfried

(person or thing that irritates or instigates)

Störenfried

(person who upsets the status quo by posing novel or upsetting questions, or attempts to stimulate innovation by being an irritant)