quitter

n (often derog 常作贬义) person who does not finish a task he has started, esp one that is done as a duty 对工作半途而废的人; （尤指对职责）不善始善终的人: I've asked you to do this for me because I know you're not a quitter. 我要求你为我做这件事, 因为我知道你做事不虎头蛇尾.

quinine, Quinquagesima, quinsy, quintessence, quintessential, quintessentially, quintet, quintuplet, quip, quire, quirk, quirkiness, quirky, quisling, quit, quite, quite a few, quite a little, quite other, quits, quiver, quixotic, quixotically, quiz, quiz-master, quizzical, quizzically, quod, quoit, quorum, quota, quotable, quotation, quotation-marks (also quotes), quote, quote from, quoth, quotidian, quotient, R,