godan ~む verb / intransitive verb:

• to become loose; to slacken (e.g. rope)
• to become less tense; to relax; to let one's guard down
• to slacken (e.g. coldness, supervision); to become lax
• to become softer (e.g. ground, facial expression); (of ice) to partially melt
• to decrease (e.g. speed)
• (of a market price) to go down slightly