fag end

Từ điển Oxford Advanced Learner 8th

ˌfag ˈend [fag end fag ends] BrE NAmE noun (BrE, informal)
1. countable the last part of a cigarette that is left after it has been smoked
•The floor was littered with fag ends.
2. singular the ~ of sth the last part of sth, especially when it is less important or interesting
•I only caught the fag end of their conversation.
•the fag end of England's industrial heyday

Word Origin:
early 17th cent. (in the sense ‘remnant’): from 15th-cent. fag ‘a flap’, of unknown origin. The current sense dates from the early 20th cent.