This dreaded issue started at some time after upgrade to OS X (Yosemite) 10.10.3.
accountsd uses about 60% CPU constantly, making the laptop hot and noisy.
I'm not using iCloud at all.
Killing it doesn't help, because it starts again quickly.
Probably related question, but it's about iOS: iPhone: What is `accountsd` and why is it using 80% CPU?