“A trick,” you say sharply, “That has taken money in” (4)
I believe the answer is:
ramp
'a trick you say sharply that' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'taken money in' is the wordplay.
'taken' becomes 'rap' (I can't justify this - if you can you should give a lot more credence to this answer).
'money' becomes 'm' (abbreviation in economics).
'in' indicates putting letters inside.
'rap' going around 'm' is 'RAMP'.
'has' is the link.
Can you help me to learn more?
(Other definitions for ramp that I've seen before include "One's inclined" , "Sloping surface; swindle" , "Inclined path" , "Sloping platform" , "cheat" .)