achievable (8)
(Other definitions for gettable that I've seen before include "Not out of reach" , "in range" , "Can be achieved" .)
'achievable' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for possible that I've seen before include "Conceivable, imaginable" , "Capable of being achieved" , "Capable of happening" , "Achievable, able to be done" , "Potential" .)