The word "over-long" denotes something that is excessively lengthy or prolonged. However, there are various antonyms or opposite words that can describe the opposite of "over-long." Some of the antonyms for "over-long" include short, brief, concise, succinct, laconic, and pithy. These words indicate something that is succinct and to the point while avoiding unnecessary elaboration. These antonyms are commonly used in writing, especially in academic assignments where brevity is essential. Using antonyms for "over-long" can help convey clarity and concision in writing and ensure that the message is clearly and effectively communicated.