Wild Arctic tours I left, showing disapproval (8)
I believe the answer is:
critical
'showing disapproval' is the definition.
'wild arctic tours i left' is the wordplay.
'wild' is an anagram indicator.
'tours' means one lot of letters goes inside another (to tour can mean to go around).
'left' becomes 'l' (common abbreviation).
'arctic' anagrammed gives 'critca'.
'critca' placed around 'i' is 'critica'.
'critica'+'l'='CRITICAL'
(Other definitions for critical that I've seen before include "Crucial, decisive" , "Extremely important" , "expressing disapproving comments" , "Urgent or carping" , "At crucial stage, or being disparaging" .)