Race odds for Dear Ruth (4)
I believe the answer is:
dart
'race' is the definition.
(I know that dart is a kind of race)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for dart that I've seen before include "shift fast" , "Run suddenly" , "flash" , "one destined to go on board?" , "Tuck; arrow" .)