1. in Und. uses.
(a) [late 16C+] (also sharker) a confidence trickster, a crooked gambler.
(b) [late 18C–1900s] a pickpocket.
2. [17C] a parasite, a hanger-on.
3. in senses of legalized extortion.
(a) [17C+] (also sharkie) a sharp operator, a crooked businessman; thus sharky adj.
(b) [late 18C–1910s] a custom house officer.
(c) [early–mid-19C] as the sharks, the press gang.
(d) [mid-19C+] a lawyer; also attrib.
(e) [1910s+] a supplier of private loans at maximum interest; a loan shark n.
(f) [1920s] (US) a pawnbroker.
(g) [1920s+] (US, also labor shark) an employment agent.
(h) [1930s] (US) a private detective.
4. in US campus uses.
(a) [mid-19C] one who deliberately misses a lesson or similar compulsory attendance; the act of choosing to miss such an attendance.
(b) [late 19C–1920s] a very intelligent or hard-working student; thus shark on stilts n., a brilliant student.
5. [late 19C] (US) an amoral, hedonistic individual.
6. in senses of expertise.
(a) [1910s+] (US) an expert, an authority.
(b) [1920s–40s] a womanizer.
(c) [1920s+] a pool shark
7. [1980s] (US black) a sharkskin suit.
8. [1990s+] (US prison) a dangerous, violent person.
9. a sardine.
[1980s+] (N.Z.) fish and chips.
[1910s+] (Aus.) a solitary swimmer swimming too far out at sea; thus shark-baiting n.; also used fig. .
1. a novice surfer.
2. the victim of a shark attack.
3. a bodyboard.
[1920s] (US Und.) a thief who robs a drunk.
[16C] a confidence man.
[1900s] weak beer or other alcohol.
[1990s+] (W.I.) a greedy person.
1. [17C] a ruffian, a thug.
2. [19C] a policeman.
3. [19C] a custom house officer.
4. [19C] a lawyer.
5. [19C] (US, also land-shark hog) a wild hog.
6. [mid-19C–1930s] a money-lender, a usurer.
7. a confidence trickster; a swindler.
8. in attrib. use of sense 7.
to practise confidence trickery, to practise stealing.
[late 19C+] (US) an expert pool player, esp. one who makes money by winning at pool.
[2010s] (US) the menstrual period.