The word "蝇营狗苟" is formed by combining two metaphorical phrases: "蝇营", which likens people's busy pursuit of petty gains to flies buzzing around seeking food, and "狗苟", which compares shameless or undignified behavior to that of dogs. Each character contributes literally: 蝇 means "fly", 营 means "to seek" or "hustle", 狗 means "dog", and 苟 means "careless" or "shameless". Together, they create a compound idiom where the animal imagery directly illustrates the human conduct of being engrossed in dishonorable or selfish activities.