There can often be more than one way to convey a concept with Chinese characters. For example, there are multiple characters for the word "Spy" in Chinese. One of the easiest to memorize and straight-forward word for spy is 耳目 Ěrmù.
Spies are not soldiers, nor fighters. A spy is someone who watches, and listens. They are gatherers and purveyors of information. Therefore it is appropriate that the characters for 耳 (ear) and 目 (eye) are combined to create 耳目, a word that means both "Spy" and "Information".
Spy films and pop culture often portray spies as action heroes with high-tech gadgets and fancy cars. Cold-war romanticism and exaggeration of the real-life operations and espionage gadgets used by many western nations and the Soviet Union during that time provided the inspiration for the pop culture spy personality. For the most part, spies were simply people recruited to pass on information that were accessible to them because of their social or professional status. 耳目 perfectly illustrates this type of spy, the eyes and ears of information.