fitful (adj.)youdaoicibaDictYouDict[fitful 词源字典]
used once by Shakespeare ("Life's fitful fever," "Macbeth," 1605) in sense of "characterized by fits," from fit (n.2) + -ful. then Revived in Romantic poetry late 18c. with a sense of "shifting, changing." Related: Fitfully (1792); fitfulness.[fitful etymology, fitful origin, 英语词源]