Notice wickedness - you need guidance (6)
I believe the answer is:
advice
'guidance' is the definition.
(I've seen this before)
'notice wickedness' is the wordplay.
'notice' becomes 'ad'.
'wickedness' becomes 'vice' (I've seen this before).
'ad'+'vice'='ADVICE'
'you need' acts as a link.
(Other definitions for advice that I've seen before include "Counsel given" , "Informed counsel" , "What lawyer offers" , "Opinion offered as to future action" , "Opinion given about what to do" .)