I would switch second name and fail (10)
I believe the answer is:
disappoint
'fail' is the definition.
(I've seen this before)
'i would switch second name' is the wordplay.
'i would' becomes 'I'd'.
'switch' says the letters should be written in reverse (I've seen 'switching' mean this (switching direction)).
'second' becomes 's' (common abbreviation).
'name' becomes 'appoint' (I can't justify this - if you can you should believe this answer much more).
'id' reversed gives 'di'.
'di'+'s'+'appoint'='DISAPPOINT'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for disappoint that I've seen before include "Let down" , "Fail to satisfy" .)