Left in charge of it, is permissible (5)
I believe the answer is:
licit
'permissible' is the definition.
(I've seen this before)
'left in charge of it' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in charge of' becomes 'ic'.
'l'+'ic'+'it'='LICIT'
'is' is the link.
(Other definitions for licit that I've seen before include "Legitimate" , "Sanctioned" , "not banned" , "Acceptable" , "Permissible" .)