to become loose; to slacken (e.g. rope); to become less tense; to relax; to slacken (e.g. coldness, supervision); to become lax; to become softer (e.g. ground, facial expression)
to loosen; to slacken; to relax (attention, efforts, etc.); to let down (one's guard); to relax (a rule); to ease (e.g. restrictions)
to become loose; to slacken; to soften