Auto-antonym

An auto-antonym (sometimes spelled autantonym), or contronym (also spelled contranym), is a word with a homograph (another word of the same spelling) which is also an antonym (a word with the opposite meaning). An auto-antonym is alternatively called an antagonym, Janus word (after the Roman god), enantiodrome, self-antonym, antilogy, or addad (Arabic, singular didd). It is a word with multiple meanings, one of which is defined as the reverse of one of its other meanings. This phenomenon is called enantiosemy, enantionymy or antilogy.

Have you ever heard of anything so marvellous?

Examples

"Alight" can mean to get on, or get off
"Buckle" can mean 'to fasten or secure' or it can mean 'collapse under weight'.
"Cleave" can mean "to cling" or "to split apart."
"Clip" can mean "attach" or "cut off" .........

It is a miracle we ever manage to understand anything at all.