With hindsight, regret suddenly grabbing rag (6)
I believe the answer is:
duster
'rag' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe there's a link between them I don't understand?
'with hindsight regret suddenly grabbing' is the wordplay.
'DUSTER' is hidden back-to-front within the letters.
However, I'm unsure how this is indicated.
Can you help me to learn more?
(Other definitions for duster that I've seen before include "Rusted (anag)" , "cleaner" , "Polishing cloth" , "yellow cloth" , "Cloth for cleaning chalk from blackboard" .)