Sphere of morbidity (3)
I believe the answer is:
orb
'sphere' is the definition.
(I know that orb is a type of sphere)
'of morbidity' is the wordplay.
'of' says the answer is hidden in the clue.
'ORB' is hidden within 'morbidity'.
(Other definitions for orb that I've seen before include "The World" , "Ceremonial globe carried by a monarch" , "Spherical object or shape" , "Spherical symbol of monarch's power" , "ball with cross" .)