Cat chased by dogs, possibly very fast ones (8)
I believe the answer is:
whippets
'fast ones' is the definition.
Although both the answer and definition are plural nouns, I don't understand how one could define the other.
'cat chased by dogs possibly' is the wordplay.
'cat' becomes 'whip' (cat o' nine tails or cat is a type of whip).
'chased by' is a charade indicator (letters next to each other) (some letters chase after others).
'dogs possibly' becomes 'pets' (dogs are often kept as pets).
'whip'+'pets'='WHIPPETS'
'very' is the link.
Can you help me to learn more?
(Other definitions for whippets that I've seen before include "Little dogs" , "Small slender dogs, like greyhounds" , "Small swift dogs" , "Small racing dogs like greyhounds" .)