painstaking

US /ˈpeɪnzˌteɪ.kɪŋ/
UK /ˈpeɪnzˌteɪ.kɪŋ/
"painstaking" picture
1.

done with great care and thoroughness

:
•
The artist made a painstaking effort to capture every detail.
•
It took years of painstaking research to complete the book.
:
meticulousthoroughcarefuldiligentconscientious