Spooner’s giant bottom has partition (8)
I believe the answer is:
bulkhead
'partition' is the definition.
(bulkhead is a kind of partition)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bulkhead that I've seen before include "Upright partition in ship or aircraft" , "Separating wall in ship" , "Separator in ship" , "Interior partition in a ship or aircraft" , "piece of partitioning" .)