Student or Learner
It's normally written cat o' nine tails or cat-o'-nine-tails. I doubt that I've heard it spoken even once in my life, but it is certainly not obsolete. Perhaps it has a whiff of the archaic about it.
According to the wikipedia article, the implement is still in use in several countries.
Last edited by probus; 23-Feb-2013 at 05:49.