Moronic sap fabricated likeness (10)
I believe the answer is:
comparison
'likeness' is the definition.
(comparison is a kind of likeness)
'moronic sap fabricated' is the wordplay.
'fabricated' is an anagram indicator.
'moronic'+'sap'='moronicsap'
'moronicsap' anagrammed gives 'COMPARISON'.
(Other definitions for comparison that I've seen before include "Analogy; likeness" , "Process of identifying differences" , "distinction" , "In contrast" , "Assessment of differences" .)