Swimmers having a bit of sport with a rising star (6)
I believe the answer is:
sprats
'swimmers' is the definition.
Although both the answer and definition are plural nouns, I don't understand how they can define each other.
'a bit of sport with a rising star' is the wordplay.
'a bit of sport' becomes 'sp' (I am not sure about this - if you are sure you should believe this answer much more).
'with' means one lot of letters go next to another.
'a rising' shows that the letters should be reversed in order (letters written upwards in a down clue).
'star' back-to-front is 'rats'.
'sp'+'rats'='SPRATS'
'having' is the link.
Can you help me to learn more?
(Other definitions for sprats that I've seen before include "Small fish used to catch larger ones" , "Small marine fish of the herring family" , "'Fish, like small herrings (6)'" , "Use them to catch mackerel" , "Small fish, set to catch whales" .)