Great power could possibly ... (5)

I believe the answer is:

might

This clue is a double definition.

'great power' is the first definition.
(I've seen this before)

'could possibly' is the second definition.
(I've seen this before)

(Other definitions for might that I've seen before include "is not unlikely to" , "May, in the past" , "word expressing possibility" , "- - and main" , "Physical strength of old" .)

I've seen this clue in The Times.

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