Relating to river — nothing to do with ears! (7)
I believe the answer is:
nilotic
'relating to river' is the definition.
(relating to the River Nile)
'nothing to do with ears' is the wordplay.
'nothing' becomes 'nil' (eg nil is zero in football).
'to do with ears' becomes 'otic' (otic means relating to the ears).
'nil'+'otic'='NILOTIC'
(Other definitions for nilotic that I've seen before include "of African people" , "In Africa such tongues" , "Group of East African languages" , "tongue of Africans" , "Of Africa's longest river" .)