昭然若揭 is a four-character idiom meaning 'abundantly clear' or 'plainly evident'. It literally describes something so obvious that it's like it has been uncovered or revealed. You can use it to emphasize that a fact, truth, or someone's intention is unmistakably clear, often in a negative context (e.g., a lie, a hidden motive). It typically functions as a predicate or attribute in a sentence.