Coin falling into one's hands in just seconds (4)
I believe the answer is:
anna
'coin' is the definition.
(I have seen 'Old coin' mean 'anna' so perhaps 'coin' could also mean 'anna')
'falling into one's hands in just seconds' is the wordplay.
I cannot quite see how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is found in the answer.
The remaining letters 'na' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for anna that I've seen before include "copper, once, in India" , "Girl's name (palindrome)" , "Massey, Sewell or Karenina" , "-- Wintour, editor" , "was of very small account in India" .)