Blast! ... almost late rising (4)
I believe the answer is:
drat
'blast' is the definition.
(I've seen this before)
'almost late rising' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'late' becomes 'tardy' (synonyms).
'rising' is a reversal indicator (in a down clue, letters go up).
'tardy' with its last letter removed is 'tard'.
'tard' in reverse letter order is 'DRAT'.
(Other definitions for drat that I've seen before include "Blow!" , "Minced oath" , "Expression of annoyance on DART" , "Mild expletive" , "Exclamation of annoyance" .)