Design alien world (6)

I believe the answer is:

planet

'world' is the definition.
(I know that world can be written as planet)

'design alien' is the wordplay.
'design' becomes 'plan' (synonyms).
'alien' becomes 'et' (extra terrestrial).
'plan'+'et'='PLANET'

(Other definitions for planet that I've seen before include "Large body orbiting sun" , "body in orbit" , "Venus, for example" , "Heavenly (or earthly!) body" , "Eg, a ruby" .)

I've seen this clue in The Telegraph.

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