Start delayed as weather nasty, originally (4)
I believe the answer is:
dawn
'start' is the definition.
(dawn is a kind of start)
'delayed as weather nasty originally' is the wordplay.
'originally' suggests taking the first letters.
The first letters of 'delayed as weather nasty' is 'DAWN'.
(Other definitions for dawn that I've seen before include "Aurora, poetically" , "Cockcrow" , "Break of day" , "Aurora was its goddess" , "Daybreak" .)