Conscientious (8)
I believe the answer is:
diligent
'conscientious' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for diligent that I've seen before include "Attentive and busy" , "Painstaking - I tingled (anag)" , "Thorough" , "I tingled, being hard-working and meticulous" , "Steady in application and industry" .)