Spongy sphere in middle of somewhere else (9)
I believe the answer is:
absorbent
'spongy' is the definition.
(similar in meaning)
'sphere in middle of somewhere else' is the wordplay.
'sphere' becomes 'orb' (orb is a kind of sphere).
'in middle of' indicates putting letters inside.
'somewhere else' becomes 'absent' (somebody absent is somewhere else).
'orb' put inside 'absent' is 'ABSORBENT'.
(Other definitions for absorbent that I've seen before include "Such material is able to take in water" , "Sucking up liquid" , "Able to soak up moisture" , "receptive" , "Able to mop up" .)