From Longman Dictionary of Contemporary Englishtone something ↔ down phrasal verb1 REDUCEto reduce the effect of something such as a speech or piece of writing, so that people will not be offended His advisers told him to tone down his speech.2 CCto make a colour less bright Blue can be used to tone down very sunny rooms. → tone→ See Verb table
Examples from the Corpus
tone down• But a remnant of caution urged that she tone it down, after all, Lucy ... She began.• I have to ask them to tone it down all the time.• To reassure her, we tone ourselves down and become more reserved with Manuel.• Instead of toning himself down, to broaden his appeal, he toned himself up, and hit his 30 percent ceiling. 