Consequence minor, but tiresome (7)
I believe the answer is:
endless
'tiresome' is the definition.
Both the answer and definition are adjectives. Perhaps you can see an association between them that I can't see?
'consequence minor' is the wordplay.
'consequence' becomes 'end' (I've seen this in another clue).
'minor' becomes 'less' (I've seen this before).
'end'+'less'='ENDLESS'
'but' is the link.
Can you help me to learn more?
(Other definitions for endless that I've seen before include "Continuous - eternal - incessant" , "Sister of Aaron (Exodus)" , "Continuing too long" , "'Eternal, perpetual (7)'" , "without finishing" .)