Cash short? Study. Cash missing upfront? Study (4)
I believe the answer is:
read
'study' is the definition.
(synonyms)
'cash short?' is the wordplay.
'cash' becomes 'ready' (ready can informally refer to cash).
'short?' means to remove the last letter (I've seen 'shorter' mean this).
'ready' with its last letter taken off is 'READ'.
'study cash missing upfront?' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for read that I've seen before include "Measure energy or fuel consumption" , "(Of passage) have a certain wording" , "Use a book" , "Interpret printed matter" , "Stomach" .)