Willing to study, having the yen (5)
I believe the answer is:
ready
'willing' is the definition.
('ready' can be similar in meaning to 'willing')
'study having the yen' is the wordplay.
'study' becomes 'read' ('read' can be a synonym of 'study').
'having' says to put letters next to each other.
'the yen' becomes 'y'.
'read'+'y'='READY'
'to' is the link.
(Other definitions for ready that I've seen before include "bread" , "for immediate use" , "Willing (to do something), prepare" , "In addition" , "Willing (to do something); cash" .)