killerwhale

As a noun dolphin is

a carnivorous aquatic mammal inhabiting mostly in the shallower seas of the continental shelves, famed for its intelligence and occasional willingness to approach humans or dolphin can be (nautical) a man-made semi submerged maritime structure, usually installed to provide a fixed structure for temporary mooring, to prevent ships from drifting to shallow water or to serve as base for navigational aids.

As a noun shark is

a scaleless, predatory fish of the superorder selachimorpha, with a cartilaginous skeleton and 5 to 7 gill slits on each side of its head or shark can be (informal|derogatory) a sleazy and amoral lawyer; an ambulance chaser.

As a verb shark is

(obsolete) to steal or obtain through fraud or shark can be (obsolete) to pick or gather indiscriminately or covertly.