Put off post office interrupting mail to northeast (8)
I believe the answer is:
postpone
'put off' is the definition.
(synonyms)
'post office interrupting mail to northeast' is the wordplay.
'post office' becomes 'po' (abbreviation).
'interrupting' means one lot of letters goes inside another.
'mail' becomes 'post' (synonyms).
'to northeast' becomes 'NE' (abbreviation).
'post'+'ne'='postne'
'po' put inside 'postne' is 'POSTPONE'.
(Other definitions for postpone that I've seen before include "pigeon-hole" , "Put off till another time" , "Put off, defer" , "'Hold over, defer (8)'" , "'Put off, delay (8)'" .)