Young lady I will take on assignment (7)
I believe the answer is:
mission
'assignment' is the definition.
(mission is a kind of assignment)
'young lady i will take on' is the wordplay.
'young lady' becomes 'miss' ('miss' can be a synonym of 'young lady'**).
'will take' is a charade indicator (letters next to each other).
'miss'+'i'+'on'='MISSION'
(Other definitions for mission that I've seen before include "1996 Tom Cruise spy film -- extremely dangerous assignment" , "Assignment - calling" , "religious establishment" , "Very dangerous assignment -- Tom Cruise film series" , "In religious campaign" .)