Crossword Genius

Gum boot (informal) (5)

Ross

I believe the answer is:

welly

(Other definitions for welly that I've seen before include "Power (inf)" , "Oomph" , "One going on foot" , "Boot (informal)" , "wet-weather gear" .)

I've seen this clue in The Guardian.
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.