The word 感染 is formed by combining two characters, each contributing a key concept to create a unified meaning. 感 (gǎn) carries the core idea of "feeling" or "being affected", while 染 (rǎn) means "to dye" or "to be contaminated". Together, they metaphorically depict a process where an external influence, like a dye spreading through fabric or a pathogen entering a body, penetrates and affects the internal state, resulting in the combined sense of "infection" (physical) or "deeply affecting" (emotional). The formation is a logical, almost pictorial, merger of cause and effect.