John le Carre wrote fiction espionage novels. Espionage novels are novels which focus on a spy's life or spying in general. His most famous work is The Spy That Came In from the Cold.
The definition of a ditz is slang for someone who is silly or who seems to have scattered thinking. An example of ditz is a silly dumb person who just giggles all day. ditz. Slang a person thought of as being flighty, eccentric, silly, etc. ditz.
The hertz, Hz, is the derived SI unit of frequency. The frequency of a sound wave determines its tone and pitch. The frequency range of a young person is about 20 to 20,000 hertz. The human ear is capable of hearing many of the sounds produced in nature, but certainly not all.