nettlesome

adjective2

1. •
   Causing irritation, annoyance, or discomfort; bothersome, irksome.

   • My old car is very nettlesome.
2. •
   Thorny; difficult to deal with, especially due to being complex or tricky.

   • The task of proving Fermat’s “last” theorem remains nettlesome.
   • Be careful what you say to him; he's a nettlesome fellow.