Urge rascal to turn lions out (9)
I believe the answer is:
impulsion
'urge' is the definition.
(I've seen this before)
'rascal to turn lions out' is the wordplay.
'rascal' becomes 'imp' (synonyms).
'to turn' becomes 'u' (a 'U-turn' is a kind of turn).
'out' is an anagram indicator (out can mean wrong or inaccurate).
'lions' is an anagram of 'lsion'.
'imp'+'u'+'lsion'='IMPULSION'
(Other definitions for impulsion that I've seen before include "Force" , "Urge" .)