caper
词根词缀：
caper v. 欢蹦，跳跃
capr的变体，山羊总爱蹦跳
caprice n. 突变；任性
来自拉丁文capra山羊，山羊吃草会突然跳向一旁，而后又若无其事地继续吃。词义就是从这里引申而来的。
capricious adj. 变化无常的；任性的
capric〔e〕突变；任性（来自拉丁 + ious 有…性质的，关于…的 → 像山羊一样变化无常的 → 变化无常的
数据来源：新东方英语词汇速记大全
相关例句：
He is planning his next caper& the stick-up of the city bank.
他正在计划下一次的违法勾当&抢劫市银行。
A lot of people around here, including some members of the board, are worried about that British caper.
好多人，包括一些董事会成员，都对这个英国把戏感到担心。
One side is lush, with caper bushes, palm trees, and intensely colored wildflowers.
一边是绿意盎然，有马槟榔灌木、棕榈树和五彩缤纷的野花。
Pearl, looking at this bright wonder of a house, began to caper and dance, and imperatively required that the whole breadth of sunshine should be stripped off its front, and given her to play with.
珠儿望着这幢灿烂而奇妙的住宅，开始雀跃起来，使劲要求从住宅前腿上把整整一层阳光给剥下来，好让她玩个痛快。
The girl's caper cost her a twisted ankle.
小姑娘又蹦又跳，结果扭伤了脚踝。
The reappearance of The Grand Budapest Hotel, a lighthearted caper set in a rambling Eastern European hotel that was released early in the year, has leavened an awards season that has otherwise been laced with weightier drama.
今年年初上映的《布达佩斯大饭店》是一个轻松的诈骗故事，发生在一家杂乱无章的东欧酒店里，它为这个充满沉重题材的颁奖季增添了活跃的因素。