R. S. Ginzburg, S. S. Khidekel, G. Y. Knyazeva, A. A. Sankin a course in modern english

can be easily found as a part of the quotation from Shakespeare “It is the green-eyed monster which doth mock the meat it feeds on” (Othello, II, i. 165). In Modern English, however, it functions as a non-motivated self-contained phraseological unit and is also used to denote the T.V. set. Achilles heel — ‘the weak spot in a man’s circumstances or character’ can be traced back to mythology, but it seems that in Modern English this word-group functions as a phraseological unit largely because most English speakers do not connect it with the myth from which it was extracted.