Move initially giving scope (6)
I believe the answer is:
gambit
'move' is the definition.
(gambit is a kind of move)
'initially giving scope' is the wordplay.
'initially' indicates taking the first letters.
'scope' becomes 'ambit' (synonyms).
The initial letter of 'giving' is 'g'.
'g'+'ambit'='GAMBIT'
(Other definitions for gambit that I've seen before include "Opening move to gain advantage" , "Initial move found in bag, Tim" , "in school scrap" , "Sacrificial chess opening" , "Opening manouevre" .)