fill (one's) boots

1. To take or obtain as much of something as one can. Primarily heard in UK. Since the shop announced its going-out-of-business sale, customers have been filling their boots with formerly overpriced homeware. Come on, you don't need to fill your boots with everything in sight. We're still going to have access to supermarkets stores on our trip! If you're giving things away for free, people will fill their boots whether they could actually use your items!

2. To replace one in some role; to take over for one in some position. You do so much for the company that I don't see how anyone could fill your boots. I know Marcia was really popular and that it will be hard to fill her boots—but I'm going to try my best! How am I supposed to fill Stan's boots? The man was with the company for 40 years!

fill your boots

BRITISH, INFORMAL

If you fill your boots with something valuable, you get as much of it as you can. The fight has attracted a lot of people to the area, and traders have been filling their boots.

fill your boots

take full advantage of an opportunity to benefit yourself. British informal

2001 Sunday Herald By April 7, the Pitman factor will have reduced his price to about 12/1 so go on, fill your boots.