Queen sent up having lost a country (5)
I believe the answer is:
niger
'country' is the definition.
(African country)
'queen sent up having lost a' is the wordplay.
I cannot really understand how this works, but
'queen' could be 'er' (abbreviation for Elizabeth Regina) and 'er' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for niger that I've seen before include "West African republic" , "African state and river" , "22 across (anag) -- northwest African river" , "Country W. of Chad" , "Landlocked W African republic" .)