Feasible, achievable (8)
I believe the answer is:
possible
I believe this is a double definition.
'feasible' is the first definition.
(similar in meaning)
'achievable' is the second definition.
(similar in meaning)
(Other definitions for possible that I've seen before include "Achievable, able to be done" , "Capable of being achieved" , "Feasible achievable" , "Capable of happening" , "Conceivable, practicable" .)