Jerry's content: or making blunder (5)
I believe the answer is:
error
'blunder' is the definition.
(I've seen this before)
'jerry's content or' is the wordplay.
'content' means to look at the middle letters.
The centre of 'jerry' is 'err'.
'err'+'or'='ERROR'
'making' acts as a link.
(Other definitions for error that I've seen before include "1 down" , "Solecism" , "Bloomer, blunder" , "Boo-boo" , "Slip, mistake" .)