Remove duplicate keywords in adwords - how?

Keywords tab, sort by keyword text so duplicates sit next to each other, then pause the one in the weaker ad group. Google Ads Editor is much faster for a big account: Tools > Find duplicate keywords, it lists them by match type and campaign and you can bulk pause from there. Bear in mind the same keyword in a different match type isn't really a duplicate, and a duplicate across two campaigns targeting different locations is fine too. It only matters when they're competing in the same auction.