Blast! (4)
There are a few possibilities for this:
explosion
'blast' is the definition.
(a blast of air)
This is the entire clue.
(Other definitions for gust that I've seen before include "A big blow" , "Flurry" , "Squall" , "14 [OUTBURST]" , "Burst of strong wind" .)
'blast' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for drat that I've seen before include "Exclamation of annoyance" , "Expression of mild annoyance" , "blast" , "Expression of annoyance on DART" , "Informal expression of annoyance" .)
'blast' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for explosion that I've seen before include "Sudden outburst" , "Report" , "Violent outburst" , "Violent release of energy" , "Big bang" .)