Coin put in trust not long ago (8)
I believe the answer is:
recently
'not long ago' is the definition.
(I've seen this before)
'coin put in trust' is the wordplay.
'coin' becomes 'cent' (cent is a kind of coin).
'put in' indicates putting letters inside.
'trust' becomes 'rely' (to rely on is to trust).
'cent' inserted inside 'rely' is 'RECENTLY'.
(Other definitions for recently that I've seen before include "In the near past" , "Lately" , "Adverb meaning not long ago" , "Of late" , "Not so long since" .)