Has the necessary resources to overthrow Mediterranean island (4)

I believe the answer is:
able
'has the necessary resources' is the definition.
I can't tell whether this defines the answer.
'overthrow mediterranean island' is the wordplay.
'overthrow' is a reversal indicator.
'mediterranean island' becomes 'elba' (Elba is an island of the Mediterranean).
'elba' back-to-front is 'ABLE'.
'to' is the link.
Can you help me to learn more?
(Other definitions for able that I've seen before include "Competent, having ability" , "Having great proficiency or intelligence" , "Of high proficiency" , "With the required capacities" , "Bright" .)
