Boastful, being above the general level (5)
I believe the answer is:
proud
'boastful' is the definition.
(similar in meaning)
'being above the general level' is the wordplay.
'being' becomes 'pro' (pro is a kind of being).
'above' means one lot of letters go next to another (in a down clue, some letters go above others).
'the general level' becomes 'ud' (I can't justify this - if you can you should give a lot more credence to this answer).
'pro'+'ud'='PROUD'
Can you help me to learn more?
(Other definitions for proud that I've seen before include "Walking tall" , "Slightly projecting; imposing" , "Having a high opinion of oneself" , "Self-satisfied - stately - protruding" , "Stuck-up" .)