When it comes to finding synonyms for "more slackening," there are various words that come to mind. Some of these synonyms include "loosening," "relaxing," "easing," "slackening off," "letting up," "decreasing," "reducing," "weakening," "desisting," and "lessening." All of these words are related to the concept of slowing down, reducing the intensity, or becoming less strict. Depending on the context in which they are used, they can be used interchangeably with "more slackening" to convey the same or similar meaning. Ultimately, the choice of synonyms used will depend on the tone, style, and desired impact of the text.