Which word refers to falling or lying down heavily and noisily or failing utterly?

The word that best describes the action of falling or lying down heavily and noisily, or failing utterly, is "flop." This term conveys not just the physical act of dropping or collapsing but also the emotional weight of failure, especially in contexts like performances, projects, or endeavors that do not meet expectations. The essence of "flop" captures both the literal sense of a heavy fall and the metaphorical sense of a complete failure, making it the most appropriate choice.

In contrast, the other words do not align with this definition. "Fragile" refers to something that is delicate and easily broken, which does not fit the context of a heavy fall or failure. "Flamboyant" describes something that is flashy or extravagant, often in a positive way, and does not relate to the notion of falling or failing. "Forage" pertains to searching for food or provisions, which is an entirely different action and concept. Thus, "flop" stands out as the word that accurately encapsulates the two meanings in the question.