Most important couple may get spliced (9)
I believe the answer is:
mainbrace
'may get spliced' is the definition.
I can't tell whether this 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" .)