Rob destroyed sphere (3)
I believe the answer is:
orb
'sphere' is the definition.
(I know that orb is a type of sphere)
'rob destroyed' is the wordplay.
'destroyed' indicates anagramming the letters.
'rob' anagrammed gives 'ORB'.
(Other definitions for orb that I've seen before include "Jewelled ornament" , "A sphere or globe" , "A poetic eye, bro" , "Item of insignia" , "Royal sphere (paired with 13 across)" .)