The phrase "such that cannot be encompassed with outstretched arms" is often used to describe something grand or vast that is difficult to comprehend or measure. Synonyms for this phrase include boundless, immeasurable, infinite, limitless, and vast. These words convey the idea that something is beyond the scope of what can be easily quantified or contained. They also suggest a sense of awe or wonder that comes with encountering something so immense. Whether used to describe the expansiveness of the universe, the depths of human emotion, or the complexity of a problem, these synonyms provide a way to express the magnitude and impact of that which is beyond our grasp.