what is neurosis?

cookiesOxford English Dictionary

neurosis (n.) -

1. Med. and Psychol. Originally: any disease or disorder characterized by abnormal nervous or mental function, esp. when unaccompanied by other systemic or local disease; a primary or functional neurological disease or disorder (now hist.). Later: psychological disorder in which there is disabling or distressing anxiety, without severe disorganization or distortion of behaviour or personality (cf. PSYCHOSIS n. 1); an instance or type of this.