Contranyms, also known as auto-antonyms, are a linguistic phenomenon that can trip up inexperienced human translators and machine translation systems. What is a contranym?

Contranym: a word with two opposite meanings, e.g. sanction (which can mean both ‘a penalty for disobeying a law’ and ‘official permission or approval for an action’).

Let’s look at some examples:

Clip can mean “attach” or “cut off”.

Ambiguous sentence: “I’m going to clip that.” Are we applying a barrette to hair or trimming a floral arrangement? Or might this refer to making a short video clip?

Dust can mean “to remove dust (cleaning a house)” or “to add dust” (e.g. to dust a cake with powdered sugar).

Ambiguous sentence: “Dust that.” Are we cleaning a shelf or sprinkling powdered sugar on a cake?

Oversight can mean “accidental omission or error”, or “close scrutiny and control”.

Ambiguous sentence: “Their oversight caused delays.” Were the delays caused by an accidental omission or by close scrutiny?

In each instance, context is the key to understanding. An experienced translator will be aware of contranyms in both the source and target languages, and skillfully discern the correct meaning from contextual clues in the surrounding text. What are your favorite contranyms in English or a different language?

Read more about contranyms on Wikipedia.