Honest sailor, with love, over bad upset (5,5)
I believe the answer is:
above board
'honest' is the definition.
(I've seen this before)
'sailor with love over bad upset' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'with love' becomes 'o' (In tennis, 'love' means 'zero'. I am not sure about the 'with' bit.**).
'upset' indicates an anagram.
'over'+'bad'='overbad'
'overbad' anagrammed gives 'veboard'.
'ab'+'o'+'veboard'='ABOVE-BOARD'
Can you help me to learn more?
(Other definitions for above board that I've seen before include "honestly!" , "On the level" , "Fairly and squarely" , "MD is" , "Surfer's position should be this" .)