pluck
n.
c.1400, "act of plucking," from pluck, v.. Meaning "courage, boldness" (1785), originally in pugilism slang, is a figurative use from earlier meaning "heart, viscera" (1610s) as that which is "plucked" from slaughtered livestock. Perhaps influenced by figurative use of the verb in pluck up (one's courage, etc.), attested from c.1300.
v.
late Old English ploccian, pluccian "pull off, cull," from West Germanic *plokken (cognates: Middle Low German plucken, Middle Dutch plocken, Dutch plukken, Flemish plokken, German pflücken), perhaps from Vulgar Latin *piluccare (source of Old French peluchier, late 12c.; Italian piluccare), a frequentative, ultimately from Latin pilare "pull out hair," from pilus "hair" (see pile, n.3). But despite the similarities, OED finds difficulties with this and cites gaps in historical evidence. Related: Plucked; plucking.
To pluck a rose, an expression said to be used by women for going to the necessary house, which in the country usually stands in the garden. [F. Grose, "Classical Dictionary of the Vulgar Tongue," 1785]
This euphemistic use is attested from 1610s. To pluck up "summon up" is from c.1300.