Inconsiderate yet benevolent, ultimately? Not so (11)
I believe the answer is:
thoughtless
'inconsiderate' is the definition.
('thoughtless' can be similar in meaning to 'inconsiderate')
'yet benevolent ultimately? not so' is the wordplay.
'yet' becomes 'though'.
'ultimately?' says to take the final letters (I've seen 'ultimately' mean this).
'not so' becomes 'less' (I've seen this before).
The last letter of 'benevolent' is 't'.
'though'+'t'+'less'='THOUGHTLESS'
(Other definitions for thoughtless that I've seen before include "Insensitive" , "Uncaring" , "Showing little consideration for others" , "Lacking consideration" , "Inconsiderate - reckless" .)