Good lie concocted ending in dodgy set of beliefs (8)
I believe the answer is:
ideology
'set of beliefs' is the definition.
(I've seen this before)
'good lie concocted ending in dodgy' is the wordplay.
'concocted' indicates anagramming the letters.
'ending in' says to take the final letters.
The final letter of 'dodgy' is 'y'.
'good'+'lie'='goodlie'
'goodlie' anagrammed gives 'ideolog'.
'ideolog'+'y'='IDEOLOGY'
(Other definitions for ideology that I've seen before include "Beliefs forming basis of political philosophy, say Marxism" , "An ism" , "Ideas that form the basis of a political theory" , "Belief system" , "Ideas forming basis of political theory" .)