Be more indifferent and negligent (8)
I believe the answer is:
careless
'negligent' is the definition.
(associated in meaning)
'be more indifferent' is the wordplay.
I cannot quite see how this works, but
'be' could be 'are' (I've seen this in another clue) and 'are' is present in the answer.
This explanation may well be incorrect...
'and' is the link.
Can you help me to learn more?
(Other definitions for careless that I've seen before include "Inattentive to risk" , "Not careful or thorough enough" , "'Heedless, unthinking (8)'" , "Negligent - nonchalant" , "Sloppy" .)