The word "紧张" is formed through a vivid conceptual metaphor that combines two physical sensations to describe a psychological state. The first character, "紧" (jǐn), means tight or tense, as in a taut rope. The second, "张" (zhāng), means stretched or expanded, like a drawn bowstring. Together, they create the image of something being pulled tightly to its limit, which is then applied abstractly to convey the feeling of being mentally strained, nervous, or under intense pressure, as if one's own nerves or situation are stretched tight.