Pronunciation: (non-gon"u-kok'ul),[key]Pathol. a widespread sexually transmitted infection of the urethra, caused by the parasite Chlamydia trachomatis, or the mycoplasm Ureaplasma urealyticum, characterized in males by painful urination and discharge from the penis and in females by frequent, painful urination and cervical erosion. Abbr.: NGU Also called nonspecific urethritis. Cf. chlamydia.