Fed up with the rheumatism? (5,5)
I believe the answer is:
bored stiff
'fed up with the rheumatism?' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'fed up with the rheumatism?' is the wordplay.
'fed up' becomes 'bored' (fed up can mean bored).
'with' means one lot of letters go next to another.
'the rheumatism?' becomes 'stiff' (I can't justify this - if you can you should believe this answer much more).
'bored'+'stiff'='BORED STIFF'
Can you help me to learn more?
(Other definitions for bored stiff that I've seen before include "Suffering tedium" , "Very fed up" , "Extremely uninterested" .)