Revolutionary Cuba hides one very old camp (7)
I believe the answer is:
bivouac
'camp' is the definition.
(I know that camp can be written as bivouac)
'revolutionary cuba hides one very old' is the wordplay.
'revolutionary' indicates an anagram.
'hides' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'very' becomes 'v' (abbreviation).
'old' becomes 'o' (abbreviation).
'cuba' with letters rearranged gives 'buac'.
'i'+'v'+'o'='ivo'
'buac' placed around 'ivo' is 'BIVOUAC'.
(Other definitions for bivouac that I've seen before include "Temporary and basic encampment" , "Temporary camp without tents or cover" , "Camp in the open" , "A temporary army camp" , "Encamp" .)