Together, the West Indies and Germany are expansive (4)
I believe the answer is:
wide
'expansive' is the definition.
(I've seen this before)
'together the west indies and germany' is the wordplay.
'together' becomes 'w' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'the west' indicates taking the first letters (I've seen 'west of' mean this (most west - leftmost - letter)).
'and' is a charade indicator (letters next to each other).
'germany' becomes 'de' (standard two letter abbreviation - Deutschland).
The first letter of 'indies' is 'i'.
'w'+'i'+'de'='WIDE'
'are' is the link.
Can you help me to learn more?
(Other definitions for wide that I've seen before include "Far from the target" , "Extensive" , "Spacious; an extra" , "roomy" , "Expansive" .)