/ʃɑ:k; ʃɑrk/
n
1 any of various types of sea-fish with a triangular fin on its back, some of which are large and dangerous to bathers 鲨鱼.
2 (infml derog 口, 贬) person who extorts money from others or lends money at very high interest rates; swindler 敲诈勒索的人; 放高利贷的人; 骗子.

n[C]

[Sense: 1; Date: 1400-1500; Origin: Origin unknown.]
[Sense: 2; Date: 1500-1600; Origin: Probably from German schurke 'bad man'; influenced by SHARK1]
pluralsharkorsharks
a large sea fish with several rows of very sharp teeth that is considered to be dangerous to humans
　Sharks were circling around our boat.
shark-infested waters
(=waters where there are a lot of sharks)
informal someone who cheats other people out of money
pool/card shark
(=someone who uses their skill at pool or cards to cheat other players out of money )
→loan shark