Gamora is the adopted daughter of galactic warlord Thanos, but turns against her mentor to become a force for good as a member of the Guardians of the Galaxy.
"Gamora is this stealth assassin," Saldana says in the clip. "She's relentless. She's lethal. She's rough!"
There is also an exclusive look at battle scenes from the movie which allow Gamora to show off her expert fighting skills.
The rest of the Guardians of the Galaxy team is comprised of Chris Pratt as the human Star-Lord, WWE star Dave Bautista as the warrior Drax the Destroyer, Vin Diesel as tee-like being Groot and Bradley Cooper voicing genetically-modified raccoon Rocket.
Together they must stop the Kree radical Ronan and his cronies' (Karen Gillan, Djimon Hounsou) plot to eradicate the Xandarian race.
Guardians of the Galaxy - which is directed by James Gunn – opens on August 1 in the US and on July 31 in the UK.
Watch an extended preview for the Marvel Studios movie below: