The antonyms for the phrase "enlarge on or upon" include compress, decrease, diminish, narrow, shorten, and simplify. When we talk about enlarging on or upon a topic, we mean to expand, elaborate, or provide additional details about it. However, the antonyms suggest the opposite - to reduce, limit, or make something smaller or simpler. These antonyms can be useful for writers and speakers who want to convey conciseness, clarity, or brevity in their communication. By using antonyms for enlarge on or upon, they can avoid being verbose or redundant, and instead, focus on delivering a clear and straightforward message.