Harsh or severe (especially criticism, treatment, or judgment); strict and unrelenting.
彼女の批評はいつも手厳しいが、参考になる点も多い。
Her critiques are always harsh, but they often contain useful points.
上司はミスに対して手厳しい態度を取った。
The boss took a harsh stance toward the mistake.
手厳しい指摘を受けて、改善点が明確になった。
After the severe criticism, the points to improve became clear.