Synonyms for Grampus (same or very similar meaning)
WordNet sense 1 (predatory black-and-white toothed whale with large dorsal fin; common in cold seas):
killer, orca, killer whale, Orcinus orca, sea wolfWordNet sense 2 (slaty-grey blunt-nosed dolphin common in northern seas):
Grampus griseusFrom the ODE community, based on WordNetadd/edit