refractary
/rɪˈfræktəri/ i /rɪˈfræktɔri/Definitions
1. adjective
resistant to change or treatment; stubbornly refusing to comply or obey; difficult to melt or reduce to a liquid
“The refractory patient refused to take his medication as prescribed.”
2. noun
a person or thing that is refractory
“The refractory child was a challenge for the teacher to manage.”