Way out of planet (4)
I believe the answer is:
lane
'way' is the definition.
(lane is a kind of way)
'of planet' is the wordplay.
'of' indicates the answer is hidden within the clue.
'LANE' can be found hidden inside 'planet'.
'out' acts as a link.
(Other definitions for lane that I've seen before include "Narrow rural road" , "Byroad" , "Footpath" , "Quiet road" , "Passage" .)