The phrase "sets motion" refers to the act of initiating movement or progress. Antonyms for this phrase would be words or phrases that connote a lack of movement, stillness, or stagnation. Some antonyms that can be used are stationary, motionless, static, inactive, still, dormant, idle, immobile, lifeless, and quiet. When one's actions or plans come to a halt or become inactive, it is no longer considered as setting motion. The use of antonyms can greatly strengthen one's writing as they add a variety of expressions to the piece.