Intelligence? Country that elected Bojo's losing it (6)
I believe the answer is:
brains
'intelligence?' is the definition.
(I've seen this before)
'country that elected bojo's losing it' is the wordplay.
'country that elected bojo's' becomes 'britain's' (Boris Johnson nickname).
'losing' suggests deleting specific letters.
'britains' with 'it' taken away is 'BRAINS'.
(Other definitions for brains that I've seen before include "Intelligence" , "They're all in your head" , "Minds" , "They're enclosed in skulls" , "Small seeds or lines in wood" .)