Didn’t economise – too exhausted (9)
I believe the answer is:
overspent
'exhausted' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for overspent that I've seen before include "Invested too much" , "Beyond budget" , "Bought too much" , "financial crisis" , "broke" .)