False belief of French in soul is moving (8)
I believe the answer is:
delusion
'false belief' is the definition.
(thesaurus)
'of french in soul is moving' is the wordplay.
'of french' becomes 'de'.
'is moving' is an anagram indicator.
'in'+'soul'='insoul'
'insoul' is an anagram of 'lusion'.
'de'+'lusion'='DELUSION'
(Other definitions for delusion that I've seen before include "False or mistaken belief" , "Unsoiled sort of hallucination" , "Misconception - deception" , "Mistaken belief in the face of contradictory evidence" , "False impression" .)