Chiasmus is a figure where two structures containing the same elements have them in opposite order. In St Luke's Gospel, in the Christian Bible, there is an unjust steward (manager) who is sacked. He protests, saying that he is not fit for manual work, but he is too proud to ask for money. His words are translated in the King James version (1607) as "I cannot dig; to beg I am ashamed". This is a fine example of chiasmus. The two clauses have the same basic elements, Subject + modal (auxiliary) + Verb; but while the first Clause has these elements in that order [IpnS canaux notnegmodal digverbV], the second has them in the order Verb + Subject + modal [to begverbV IpnS ammodal ashamedV]
Etymological note: The word chiasmus came into English, through New Latin, from the Greek χιασμός (chiasmos), ‘crosswise or diagonal arrangement, i.e., like the appearance of the Greek letter chi (χ)’. The Greek word was particularly used of the figure of construction we call chiasmus - and aptly so, since if the two contrasting clauses are written one above the other, the lines which join the corresponding elements in each clause form an x, the shape of the letter chi (χ) - e.g.,
I cannot dig,
To beg I am ashamed.
The adjective from chiasmus is chiastic.