The phrase "gives impetus" refers to providing momentum, energy, or motivation towards a particular action or goal. Antonyms for this phrase would be terms that imply a lack of encouragement, drive or stimulation. Some antonyms could include words like impede, thwart, discourage, hinder, or obstruct. These words indicate obstacles or setbacks that prevent progress or discourage further action. Other antonyms could include terms like idle, inactive, inactive, lethargic, or lazy, indicating a lack of energy or incentive to pursue goals. Using antonyms of "gives impetus" in a sentence would suggest a lack of momentum or motivation, and indicate a need to overcome obstacles to achieve success.