Diligent help almost keeping couple united (9)
I believe the answer is:
assiduous
'diligent' is the definition.
(similar in meaning)
'help almost keeping couple united' is the wordplay.
I cannot really see how this works, but
'help' could be 'sid' (I've seen this in another clue) and 'sid' is present in the answer.
'united' could be 'u' (abbreviation) and 'u' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for assiduous that I've seen before include "Showing great care and perseverance" , "Diligent" , "Marked by care and persistent effort" , "Hard-working" , "Persevering" .)