"I'd rather write shell scripts than Makefiles."
Blur is a very small and simple target-driven (top-down) build system, with (practically speaking) no dependencies: It is written entirely as a small handful of Bash scripts, totalling about 1,200 lines.
As of this writing, Blur is mostly an experiment and a demonstration, and not anything that's gotten much real-world use.
"Blur" doesn't stand for anything, and it's certainly not a reference to the tool's blazing fast speed. It's just a description of how the stream of tears affects its author's vision whenever he contemplates having to use Make… or do build system work in general.