buck¹ / bək/ • n. 1. the male of some antlered animals, esp. the fallow deer, roe deer, reindeer, and antelopes. Compare with doe. ∎  a male hare, rabbit, ferret, rat, or kangaroo.2. a vertical jump performed by a horse, with the head lowered, back arched, and back legs thrown out behind.3. a fashionable and typically hell-raising young man.4. inf., offens. a black or American Indian man.5. (bucks) an oxford shoe made of buckskin.• v. 1. [intr.] (of a horse) to perform a buck: he's got to get his head down to buck [tr.] she bucked them off if they tried to get on her back. ∎  (of a vehicle) make sudden jerky movements: the boat began to buck in the water.2. [tr.] oppose or resist (something that seems oppressive or inevitable): the shares bucked the market trend.3. [tr.] inf. make (someone) more cheerful: Bella and Jim need me to buck them up [intr.] (buck up) buck up, kid, it's not the end of the world. • adj. military slang lowest of a particular rank: a buck private.buck² • n. inf. a dollar: a run-down hotel room for five bucks a night.PHRASES: big bucks a lot of money.a fast (or quick) buck easily and quickly earned money: the pursuit of a fast buck is the cause of most losses.buck³ • n. an article placed as a reminder before a player whose turn it is to deal at poker.PHRASES: pass the buck inf. shift the responsibility for something to someone else.

buck
A. male of deer; †he-goat OE.;

B. †fellow XIV; gay, dashing man XVIII.
i. OE. buc male deer = OHG. boc (G. bock), ON. bukkr, bokkr :- Gmc. *bukkaz;

ii. OE. bucca he-goat = ON. bokki my good fellow, old buck :- *bukkan-; prob. of IE. orig. (cf. OIr. bocc he-goat, Arm. buc lamb, Av. būza-, Skr. bukka- he-goat).

Hence buck vb. (dial.) dress up (i.e. like a ‘buck’ or smart fellow); (sl.) cheer up; hurry up XIX.

buck2 an article placed as a reminder in front of a player whose turn it is to deal at poker.
the buck stops here the responsibility for something cannot or should not be passed to someone else. Harry Truman (1884–1974), as President of the US, had this unattributed motto on his desk.
pass the buck shift the responsibility for something to someone else.

buck1 archaic term for a fashionable and typically hellraising young man. Recorded from the early 18th century, the word initially implied spirited conduct rather than elegance of dress; the meaning of a young man regarded as being fashionable dates from the early 19th century.