Chiasmus is a rhetorical device in which two phrases are placed back to back with their grammatical structures reversed: the second clause mirrors the first, but in the opposite order. The pattern is often described as AB–BA. The witches' cry in Macbeth — 'Fair is foul, and foul is fair' — is one of the most famous examples.
What does chiasmus mean and where does the name come from?
The word chiasmus comes from the Greek letter chi (χ), which looks like an X. Trace a line from A to B in the first clause, then cross it back from B to A in the second — you draw an X, a chi. The name describes the visual cross-shape of the structure.
Chiasmus has been used since ancient times in oratory (Cicero and Aristotle both employed it) and in religious texts. It appears throughout the Bible, in classical rhetoric, and in almost every major literary tradition. At KS3, students most commonly encounter it in Shakespeare and in political speeches.
What does chiasmus look like? The AB–BA structure explained
The key feature of chiasmus is the reversal of elements. Here is the pattern broken down:
| Position | Clause 1 | Clause 2 |
|---|---|---|
| First element (A) | 'Fair' | 'foul' |
| Second element (B) | 'is foul' | 'is fair' |
| Pattern | A B | B A |
In 'Fair is foul, and foul is fair':
- Clause 1: Fair (A) is foul (B)
- Clause 2: foul (B) is fair (A)
The words are not just repeated — they are swapped. This creates a sense of the world turned upside down, which is precisely the theme Shakespeare is establishing at the opening of Macbeth.
Another clear example: 'Ask not what your country can do for you — ask what you can do for your country.' (John F. Kennedy, 1961)
- Clause 1: your country (A) can do for you (B)
- Clause 2: you (B) can do for your country (A)
The structure reversal makes the sentence feel balanced, inevitable, and memorable.
How does chiasmus differ from antithesis?
Chiasmus and antithesis are closely related and often appear together, which is why students sometimes confuse them.
Antithesis places two contrasting ideas in parallel: 'It was the best of times, it was the worst of times.' The emphasis is on the contrast of ideas.
Chiasmus reverses the grammatical order of those ideas: the emphasis is on the mirror structure. 'Fair is foul, and foul is fair' is both antithesis (foul opposes fair) and chiasmus (the order is reversed).
You can have antithesis without chiasmus (the elements are contrasted but not reversed: 'Many are called, but few are chosen'). You can also have chiasmus without clear antithesis (if the reversed elements are not opposite in meaning). But the most powerful examples are usually both at once.
What effects does chiasmus create?
| Effect | Explanation |
|---|---|
| Memorability | The symmetrical structure is pleasing to the ear and easy to remember, which is why chiasmus features so heavily in speeches and proverbs |
| Balance and elegance | The mirror shape creates a sense of poise and completeness — the sentence feels 'closed' |
| Irony and subversion | When the reversed elements are contradictory (as in 'Fair is foul'), the structure enacts the moral confusion it describes |
| Emphasis | The second clause, arriving with the structure already in the reader's ear, lands with extra weight |
Chiasmus in Shakespeare
Shakespeare uses chiasmus constantly, and recognising it can unlock analysis at KS3 and GCSE.
Macbeth, Act 1, Scene 1 — the witches:
'Fair is foul, and foul is fair: Hover through the fog and filthy air.'
The chiasmus here does more than create a memorable phrase: it announces the play's central moral disorder. In Macbeth's world, fair appearances mask foul intentions, and what looks good (Duncan's generous trust) turns out to be deadly. The AB–BA structure enacts the theme before the play has truly begun.
Othello, Act 3, Scene 3 — Iago:
'Who steals my purse steals trash… but he that filches from me my good name / Robs me of that which not enriches him, / And makes me poor indeed.'
Less a chiasmus and more a reversal of expected moral order — Shakespeare and his contemporaries used the structure fluidly.
How do you write about chiasmus in an essay?
Weaker: 'Shakespeare uses chiasmus in this quote, which is a rhetorical device.'
Stronger: 'The chiasmus "Fair is foul, and foul is fair" reverses the conventional moral order at the very opening of the play. By structurally swapping these two words — mirroring them across each other — Shakespeare suggests that in Macbeth's Scotland the customary relationship between appearance and reality has been inverted. The device is not merely decorative: its AB–BA form performs the very moral confusion the play will dramatise.'
Frequently asked questions
Is chiasmus the same as antimetabole?
Antimetabole is a specific type of chiasmus in which the exact same words are repeated but in reversed order. 'Fair is foul, and foul is fair' and Kennedy's 'Ask not what your country can do for you…' are both antimetabole. All antimetabole is chiasmus, but not all chiasmus is antimetabole — sometimes the reversal involves grammatical structures rather than repeated words. For KS3 purposes, calling both 'chiasmus' is acceptable.
Does chiasmus always involve exactly two clauses?
No. Some chiastic structures span longer passages, or involve three elements (ABC–CBA). The essential feature is the reversal, not the number of clauses. In longer literary works, critics sometimes identify 'ring composition' — a chiastic structure at the level of whole chapters or scenes, where events in the second half mirror those in the first. You are unlikely to be asked to identify this at KS3, but it is worth knowing exists.
How do I remember the term chiasmus?
Think of the Greek letter chi (χ) as an X. If you draw lines connecting A→B in the first clause to B→A in the second, you trace an X-shape. The name is a visual clue to the structure.
Where else does chiasmus appear besides Shakespeare?
Chiasmus is common in political speeches (Lincoln: 'With malice toward none; with charity for all'; Kennedy above), in religious writing (the Bible is full of chiastic structures), in proverbs ('When the going gets tough, the tough get going'), and in advertising slogans. It is a device that has been recognised as rhetorically powerful for over two thousand years, which is why it keeps appearing across so many different contexts and traditions.
Studying Shakespeare or a text with complex rhetoric? Professor Quill helps you understand the device and find your own analysis — without giving you the answer. Visit aitutors.me.