Non-specific urethritis: an infection of the urethra, the thin tube that urine leaves the body through. It often hurts to pee, and there may be a discharge. 'Non-specific' is a clinic label: doctors can see the infection, but they have not pinned it to one named germ the way they do with gonorrhoea. Though actually, a germ is often found later — frequently chlamydia. It is a medical term you meet at a sexual-health clinic, not in ordinary chat; younger doctors may say NGU (non-gonococcal urethritis) more. It is not dirty slang and not a joke. Say N-S-U.