If you look hard enough, you’ll eventually find that almost all rules in English have exceptions and even contradictions. It’s a result of it being such an expansive and adaptive language.

One of the most curious (and perhaps frustrating) areas of English that we can actually have two identical words with their own opposite meaning. That is, one word with the same sound and spelling, used in two opposite ways.

These are called contronyms, and having recently reviewed homonyms and their associated ideas, I thought it would be interesting to explore these next, along with a few tips for spotting the differences.

What are contronyms?

Contronyms, are a specific group of homonyms, words that look and sound the same, but with opposite, or nearly opposite, meanings. They are also known as contanyms, Janus words (coming from the Roman two-faced god) or auto-antonyms (referring to being their own antonym, a word of opposite meaning). For example, the verb “dust” can mean to apply dust or to remove dust.

She dusted the cake with icing sugar. (added)
She dusted the shelves so they looked nice and clean. (removed)

There’s some flexibility in how people list or define contronyms, as often the different meanings stem from a different word type, and are therefore not strictly opposites. For example, “left” might be considered a contronym, because as a verb it can mean to go away, while it is used as an adverb to describe something remaining.

He left the party early. (went away)
After the party, he was the only one left. (still there)

This isn’t an exactly opposite meaning in use, but it’s close enough.

Contronyms – Words that are their own opposites

It’s worth learning contronyms to avoid confusion, and also to expand your vocabulary. Mostly, there’s no easy way to know when these will occur, so you have to learn them individually, and look out for the context to guess which meaning is used.

So, here are some examples of contronyms, or other confusingly similar words with different meanings:

Bill (noun) – either a receipt or an invoice
Bolt (verb) – to secure something down or to move quickly away
Cleave (verb) – to bring together or to separate
Clip (verb) – to attach together or to remove a part of (e.g. truncate)
Dust (verb) – to add or to remove small particles
Fast (adverb) – quick or made stable
Finished (adjective) – completed or destroyed/ruined
Go (verb) – to move or to weaken/fail
Hold up (verb) – to support or to hinder
Left (past verb) – to have gone or Left (adverb) – remaining
Off (adjective) – deactivated or Off (part of phrasal verb) – activated (e.g. for an alarm to go off)
Peer (noun) – nobility or an equal
Refrain (verb) – to stop or Refrain (noun) a repetition
Rock (noun/adverb) – stone/solid or Rock (verb) – gentle motion back and forth
Sanction (verb) – to approve/allow or to restrict
Seed (verb) – to sow seeds or to remove them
Temper (verb) – to soften or to strengthen
Trip (noun) – a journey or Trip (verb) – to interrupt motion / stagger
Weather (verb) – to withstand or to wear away