Trouble one may have seen on Saturday night (5)
I believe the answer is:
fever
This might be a double definition.
'trouble one may' is the first definition.
The answer and definition can be both feelings as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'seen on saturday night' is the second definition.
The answer and definition can be both states of affairs as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'have' acts as a link.
Can you help me to learn more?
(Other definitions for fever that I've seen before include "1950s hit for 11" , "excited state" , "General excitement" , "State of high excitement" , "Yellow, for example" .)