One fed-up prisoner with problem about screws (8)
I believe the answer is:
consumer
'one fed-up' is the definition.
I can't tell whether this defines the answer.
'prisoner with problem about screws' is the wordplay.
'prisoner' becomes 'con' (abbreviation for 'convict').
'with' says to put letters next to each other.
'problem' becomes 'sum' (arithmetic problem).
'about screws' becomes 'er' (I can't explain this - if you can you should give a lot more credence to this answer).
'con'+'sum'+'er'='CONSUMER'
Can you help me to learn more?
(Other definitions for consumer that I've seen before include "Person who uses goods or services" , "One who buys goods" , "Person who buys goods or service" , "One buying goods" , "one may be looking for the product" .)