I. transitive verb Date: 1874 to pronounce (a sound) without lip rounding or with decreased lip rounding, to spread (the lips) laterally , II. adjective Date: 1958 pronounced with the lips not rounded
UNROUND
Meaning of UNROUND in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012