Pride oneself on having a pair even shorter (5)
I believe the answer is:
preen
'pride oneself' is the definition.
(I've seen this in another clue)
'on having a pair even shorter' is the wordplay.
'on' is a charade indicator (letters next to each other).
'having' becomes 'en' (I can't explain this - if you can you should give a lot more credence to this answer).
'a pair' becomes 'pr' (abbreviation).
'shorter' indicates taking the first letters (I've seen 'short' mean this).
The initial letter of 'even' is 'e'.
'pr'+'e'='pre'
'en' after 'pre' is 'PREEN'.
Can you help me to learn more?
(Other definitions for preen that I've seen before include "Congratulate (oneself); attend to dress" , "(Of a bird) tidy and clean feathers" , "Self-congratulate" , "Titivate oneself" , "Maintain" .)