be a thorn in fleshbe a thorn in (someone's) flesh/side
someone or something that keeps annoying you or causing you trouble.
A relentless campaigner, he was a thorn in the government's side for years.
(redirected from be a thorn in flesh)
be a thorn in (someone's) side
To be a constant or persistent cause of annoyance, frustration, or trouble. My professor was an environmental activist when he was younger, and, apparently, he was quite a thorn in the oil companies' sides at the time.
be a thorn in your ˈflesh/ˈside
be a person or thing that repeatedly annoys you or stops you doing something: This patient is a real thorn in my side. He’s always complaining of feeling sick and I can never find anything wrong with him.