Economical move essentially strategic (6)
I believe the answer is:
budget
'economical' is the definition.
(thesaurus)
'move essentially strategic' is the wordplay.
'move' becomes 'budge' (budging is a kind of moving).
'essentially' means to look at the middle letters.
The middle of 'strategic' is 't'.
'budge'+'t'='BUDGET'
(Other definitions for budget that I've seen before include "Summary of planned income and expenditure" , "Plan of spending" , "Chancellor's plan" , "Money allocated for a purpose" , "Chancellor's financial statement" .)