Holy Avenger Greater Dispel: Su or Sp?

[Wakrob]

If I use the Greater Dispel off of a Holy Avenger does that count as casting a spell? Do I provoke Opp Attacks?

"It also enables the paladin to use greater dispel magic (once per round as a standard action) at the class level of the paladin."

Thanks
Wakrob

[Diego Rossi]

It should work as a command word magic item.
Standard action that don't provoke.