Pre-eminence badly affects sergeants (9)
I believe the answer is:
greatness
'pre-eminence badly' is the definition.
I can't judge whether this defines the answer.
'affects sergeants' is the wordplay.
'affects' indicates anagramming the letters (I've seen 'affected' mean this).
'sergeants' anagrammed gives 'GREATNESS'.
Can you help me to learn more?
(Other definitions for greatness that I've seen before include "''Some achieve ..., and some have ... thrust upon ?em'' (Twelfth Night)" , "Nobility" , "Magnitude; eminence" , "Malvolio wasn't to fear being thrust into?" , "Natal attribute or achievement or something thrust upon one!" .)