The killer whale (Orcinus orca), commonly referred to as the orca, and less commonly as the blackfish, is a toothed whale belonging to the oceanic dolphin family. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas. Killer whales as a species have a diverse diet, although individual populations often specialize in particular types of prey. Some feed exclusively on fish, while others hunt marine mammals such as sea lions, seals, walruses and even large whales. Killer whales are regarded as apex predators, lacking natural predators and preying on even large sharks.
You're making a bit of a mistake. Odontoceti is Latin for "toothed whale", just as Dinosauria is Latin for "terrible lizard". However, dolphins are not whales, nor are dinosaurs lizards. Dolphins are as distinct from whales as they are from porpoises, even though all are members of the suborder Odontoceti.
The key to differentiation is the ability to hybridize. All dolphins can hybridize. Its rare, both in the wild and captivity, but it does happen. Dolphins cannot mate with whales or porpoises.
A False Killer Whale is, you guessed it, a dolphin. As is always the case through the entire catalog of Terran lifeforms, two species can only interbreed/hybridize if they are in the same genus. Dolphins, whales and porpoises are all from different families - translations of taxological names aside.