A doctor in South America listening to this? (5)
I believe the answer is:
samba
'listening to this?' is the definition.
The definition suggests a singular noun which matches the answer.
'a doctor in south america' is the wordplay.
'doctor' becomes 'mb' (Bachelor of Medicine, Medicinae Baccalaureus).
'in' means one lot of letters goes inside another.
'south' becomes 's' (synonyms).
'america' becomes 'a' (common abbreviation - e.g. in organisation names).
'a'+'mb'='amb'
's'+'a'='sa'
'amb' inserted inside 'sa' is 'SAMBA'.
(Other definitions for samba that I've seen before include "Dance, originally from Brazil" , "Brazilian dance" , "This ambassador's > brisk steps" , "Latin dance" , "it was launched in Brazil" .)