The disavow tool within Google Search Console allows you to tell Google not to consider a set of low-quality backlinks (also known as toxic backlinks) to your site. If a website with a high spam score is linking to your website, Google may penalize your site for that backlink thinking you’re attempting to add building a backlink profile via spammy means. In order to remove that penalty, you must tell Google not to take those low-quality backlinks into account to prove that your backlinking strategies are well-intentioned. You can find step-by-step instructions on using the disavow tool here.