ˈ ̷ ̷ˌ ̷ ̷ noun
Etymology: gad (I) + fly
1. : any of various flies (as a tabanid, botfly, or warble fly) that bite or annoy livestock
2. : a usually purposely annoying or provoking person ; especially : one that stimulates or provokes to activity and especially to the analysis and defense of ideas by persistent criticism especially of an irritating pointed kind
an immensely busy writer on various subjects, a gadfly to the respectable — Carl Van Doren
a gadfly , buzzing with ideas both for political strategy and the improvement of things in Oregon — U.S. News & World Report