Most important couple may get spliced (9)
I believe the answer is:
mainbrace
'may get spliced' is the definition.
I can't judge whether this definition defines the answer.
'most important couple' is the wordplay.
'most important' becomes 'main' (main can mean the most important or major).
'couple' becomes 'brace' (brace can mean a pair of something).
'main'+'brace'='MAINBRACE'
Can you help me to learn more?
(Other definitions for mainbrace that I've seen before include "that got spliced" , "rope" , "It's spliced aboard" , "may get spliced at sea" , "Part of rigging" .)