contronymy

Contronymy, a phenomenon which has received much attention in recent years, has often been described as sense opposition at the micro-level.

2008, BI Karaman, “On contronymy”, in International Journal of Lexicography, volume 21, number 2

Today the same word can mean 'wholly', 'to a considerable extent' ('Quite the little madam, aren't we?') or '(only) to some extent', 'partially' or 'somewhat' ('feeling quite tired'), though theoretical linguists explain this slightly differently: 'At the micro-level the lexical unit represents a case for contronymy of antonymy type if it can be subjected to gradation and if it comprises at least two senses which are contradictory within one aspect.'

2011, Tony Thorne, The 100 Words That Make The English, →ISBN

Kronasser (1952) and Meid (1979) argue that language change results in the occurrence of contronymy in natural language.

2013, Hye Seung Lee, “Semantics of COM”, in Selected Papers from the Seventeenth College-Wide Conference for Students in Languages, Linguistics, & Literature