Start off with a meal outside (6)
I believe the answer is:
launch
'start off' is the definition.
(thesaurus)
'a meal outside' is the wordplay.
'meal' becomes 'lunch' (lunch is a kind of meal).
'outside' indicates putting letters inside (some letters go outside others).
'a' going into 'lunch' is 'LAUNCH'.
'with' acts as a link.
(Other definitions for launch that I've seen before include "Inaugurate" , "Put a new product on the market" , "Set (a boat) afloat" , "Start - motor-driven boat" , "Set afloat or propel into action" .)