Outer planet (6)
(Other definitions for neptune that I've seen before include "revolutionary body" , "Roman god of water and the sea" , "Roman sea god - planet" , "Eighth rock from the Sun" , "extract from The Planets" .)
(Other definitions for uranus that I've seen before include "Planet discovered in 1781 by Herschel" , "Seventh rock from the sun?" , "Holst's Magician planet" , "mythological god" , "space traveller" .)