[adverb]Their baby was born prematurely and weighed only 1 kilogram.She has been forced to retire prematurely because of health problems.UVA rays from the sun can prematurely age and wrinkle the skin.His stressful job made him go prematurely grey (= made his hair turn grey).
PREMATURELY
Meaning of PREMATURELY in English
Cambridge English vocab. Кембриджский английский словарь. 2012