[adjective] - careful and using a lot of effort, or done in a careful and detailed waya diligent studentdiligent workLeo is very diligent in/about his work.Their lawyer was extremely diligent in preparing their case.The discovery was made after years of diligent research.
DILIGENT
Meaning of DILIGENT in English
Cambridge English vocab. Кембриджский английский словарь. 2012