Heartless boy in trouble backing African country (5)
I believe the answer is:
libya
'african country' is the definition.
(country in Africa)
'heartless boy in trouble backing' is the wordplay.
'heartless' means to remove the middle letters.
'in' is an insertion indicator.
'trouble' becomes 'ail' (synonyms).
'backing' says the letters should be written in reverse.
'boy' with its middle taken out is 'by'.
'ail' backwards is 'lia'.
'by' going into 'lia' is 'LIBYA'.
(Other definitions for libya that I've seen before include "North African country" , "Country in N. Africa" , "Tripoli's country" , "Assault; pester" , "North African republic" .)