1.CRITICIZEsomeone who annoys other people by criticizing them 〔爱批评别人而〕惹人讨厌的人
2.TAHBIa fly that bites cattle and horses 虻,牛虻
Examples from the Corpus
gadfly• A gadfly, a maverick, a treasured pain in the posterior.• These people are inconsequential, but they are gadflies.• Hirschfield, a wealthy political gadfly, spoke at the conference.• Which had not included Rory, the gadfly son.
Origingadfly
(1500-1600)gad“pointed stick”((13-19 centuries)) (from Old Norsegaddr) + FLY2