Fitting, suitable (3)
I believe the answer is:
apt
I believe this is a double definition.
'fitting' is the first definition.
(both mean appropriate)
'suitable' is the second definition.
(apt means appropriate or fitting)
(Other definitions for apt that I've seen before include "Apposite, appropriate" , "Having a tendency" , "Ready to learn" , "Suitable; quick to learn" , "suitable for the circumstances" .)