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.
As an adjective predacious is
.