Busy First Lady with good book during occasional feud with labour leader (8)
I believe the answer is:
eventful
'busy' is the definition.
(similar in meaning)
'during occasional feud with labour leader' is the wordplay.
'during' becomes 'event' (I can't explain this - if you can you should give a lot more credence to this answer).
'occasional' indicates alternate letters (letters taken at regular intervals or on occasion).
'with' is a charade indicator (letters next to each other).
'labour leader' becomes 'l' (the leading letter of 'labour').
The alternating letters of 'feud' are 'fu'.
'event'+'fu'+'l'='EVENTFUL'
'first lady with good book' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for eventful that I've seen before include "Busy, exciting (period)" , "Full of incidents, momentous" , "Packed with incident, lively" , "Full of noteworthy incidents" , "Full of incident, not dull" .)