The phrase "gave impetus" typically refers to giving energy, momentum, or encouragement to something or someone. Antonyms of this phrase could include words or phrases that describe hindrance, repression, or discouragement. Some possible antonyms for "gave impetus" might include "stifled progress," "opposed development," "restricted growth," or "discouraged advancement." Other antonyms could focus more on the emotional aspect of the phrase, with words like "dampened enthusiasm," "squashed motivation," or "undermined inspiration." Regardless of the specific phrasing, the antonyms of "gave impetus" would generally convey a sense of slowing down or putting a stop to forward motion or progress.