Crossword Genius

Explosive start sees the two leaders switching places (5)

Ross

I believe the answer is:

nitro

'explosive' is the definition.
(short for nitroglycerine)

I cannot understand how the remainder of the clue works.

(Other definitions for nitro that I've seen before include "Explosive liquid" , "The whole universe" , "explosive material" .)

I've seen this clue in The Independent.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.