On retirement, I blast head for unpunctuality (9)
I believe the answer is:
tardiness
'unpunctuality' is the definition.
(I've seen this before)
'on retirement i blast head' is the wordplay.
'on retirement' shows that the letters should be reversed in order (retire can mean to go back).
'blast' becomes 'drat' (I've seen this before).
'head' becomes 'ness' (ness is a headland).
'i'+'drat'='idrat'
'idrat' back-to-front is 'tardi'.
'tardi'+'ness'='TARDINESS'
'for' acts as a link.
(Other definitions for tardiness that I've seen before include "Becoming late" , "Lateness" , "being a little late" , "No quality in fast food" , "Unpunctuality" .)