In Irish province, Nationalist is wanting Trident (7)
I believe the answer is:
leister
'trident' is the definition.
(type of spear for fishing)
'in irish province nationalist is' is the wordplay.
I cannot really understand how this works, but
'is' is present in the answer.
This explanation may well be incorrect...
'wanting' acts as a link.
(Other definitions for leister that I've seen before include "instrument to pierce fish" , "Trident, spear" , "Salmon-spear" , "Fishing spear with three prongs" , "One sticking salmon" .)