"Planet of the Apes" planet (5)
I believe the answer is:
earth
'planet of the apes planet' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for earth that I've seen before include "Third planet from the Sun" , "Soil; planet" , "hideaway" , "Fox's underground lair" , "Heart of clay" .)