Some seem quite empty or just the opposite (4)
I believe the answer is:
teem
'just the opposite' is the definition.
I can't judge whether this defines the answer.
'some seem quite empty' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'TEEM' can be found hidden inside 'seem quite empty'.
'or' is the link.
Can you help me to learn more?
(Other definitions for teem that I've seen before include "Abound, swarm with" , "Bear" , "Be prolific" , "(Of rain) fall heavily" , "Bucket down" .)