Job opportunity (7)
'job opportunity?' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for opening that I've seen before include "Orifice; opportunity" , "launch" , "Aperture or opportunity" , "Aperture or first night" , "Beginning; breach" .)
(Other definitions for vacancy that I've seen before include "Unoccupied state, job or apartment" , "Opportunity" , "Lack of consideration" , "Unoccupied post" , "An opening, job or apartment" .)