Native American’s petition heard (5)
I believe the answer is:
sioux
'native american's' is the definition.
(Sioux is an example)
'petition heard' is the wordplay.
'petition' becomes 'sue' (both can mean to appeal or ask for something).
'heard' indicates a 'sounds like' (homophone) clue.
'sue' is a homophone of 'SIOUX'.
(Other definitions for sioux that I've seen before include "in Dakota" , "Native American from between Lake Michigan and the Rockies" , "North American people" , "Native American people" , "Native Americans of the northern US" .)