To speak bluntly; to say what one thinks without softening or mincing words (an idiomatic expression).
彼女は歯に衣着せないので、会議ではいつも率直な意見を言う。
She doesn't mince her words, so she always speaks frankly at meetings.
批評家は作品について歯に衣着せない書き方をし、作者を厳しく批判した。
The critic wrote bluntly about the work and harshly criticized the author.
歯に衣着せない物言いは場面によっては人を傷つけることがあるから、注意が必要だ。
Speaking bluntly can sometimes hurt people depending on the situation, so you need to be careful.