nettlesome 

Topic or subject which is not easy to discuss/understand. It may also be used in case of an issue from which it is very difficult to draw valid conclusions from, due to its complexity or the lack of expertise on the subject from the speaker, for example.

On the subject of comparing Led Zeppelin and Deep Purple in terms of guitar virtuosity, I think that's a rather nettlesome issue.

nettlesome by Xabier Rubal January 5, 2006

Nettlecombe

Where Ben and Kels formed *Teh Nameless*

OMGWTFHEDWIG!!11! YOU'RE GOING TO NETTLECOMBE! D00d!

Nettlecombe by Ben December 22, 2004

Mettlesome 

A person of great mettle; courageous.

Their horses were beasts of burden, not mettlesome chargers.

And Juliet’s mettlesome temper became the engine that fueled the drama, above all in Act III, in which she seldom leaves the stage.

Mettlesome by Saint Alabaster July 6, 2020