Grass covered by couple in annual competition
I believe the answer is:
boat race
'annual competition' is the definition.
'boat race' can be an answer for 'competition' (boat race is a kind of competition). I'm unsure of the 'annual' bit.
'grass covered by couple' is the wordplay.
'grass' becomes 'oat' (I've seen this in other clues).
'covered by' means one lot of letters goes inside another.
'couple' becomes 'brace' ('brace' can be a synonym of 'couple'**).
'oat' inserted inside 'brace' is 'BOAT-RACE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for boat race that I've seen before include "Contest on the Thames" , "Oxbridge contest" , "Varsity Putney to Mortlake contest" , "sporting event" , "crafty contest" .)