One comes round every year without delay (5)
I believe the answer is:
apace
'without delay' is the definition.
(I've seen this in another clue)
'one comes round every year' is the wordplay.
'one' becomes 'ace' (ace has a value of one in some card games).
'comes round' indicates putting letters inside.
'every year' becomes 'pa' (per annum).
'ace' enclosing 'pa' is 'APACE'.
(Other definitions for apace that I've seen before include "(Move on) swiftly" , "at high speed" , "What's quickly" , "Swiftly, quickly" , "fast" .)