Innocent Welsh banker caps yen when stopping action (4-4)
I believe the answer is:
dewy-eyed
'innocent' is the definition.
(I've seen this before)
'welsh banker caps yen when stopping action' is the wordplay.
'welsh banker caps' becomes 'wye' (I am not sure about this - if you are sure you should believe this answer much more).
'yen' becomes 'y' (resembles the symbol for the currency of Japan).
'when stopping' means one lot of letters goes inside another (stopping can mean blocking a gap).
'action' becomes 'deed' (deed is a kind of action).
'wye'+'y'='wyey'
'wyey' put into 'deed' is 'DEWY-EYED'.
Can you help me to learn more?
(Other definitions for dewy-eyed that I've seen before include "Romantically naive - on the verge of tears" , "Seeming rather tearful" , "Romantically naive and trusting" , "Sentimental with moist optics" , "Exhibiting childlike credulity" .)