Care of Bond's boss, hands Bond opening (12)
I believe the answer is:
commencement
'opening' is the definition.
('commencement' can be a synonym of 'opening')
'care of bond's boss hands bond' is the wordplay.
'care of' becomes 'co' (c/o can mean 'care of' when addressing mail).
'bond's boss' becomes 'm' (I've seen this in other clues).
'hands' becomes 'men' ('men' can be a synonym of 'hands').
'bond' becomes 'cement' (I've seen this before).
'co'+'m'+'men'+'cement'='COMMENCEMENT'
(Other definitions for commencement that I've seen before include "Origin" , "Start" , "Beginning" .)