coarsen
verb [ I or T ] uk/ˈkɔː.sən/ us/ˈkɔːr.sən/
(ROUGH)
（使）变粗；使粗糙
to become rough or cause something to become rough
In high summer, the salad leaves coarsen and become bitter.
He coarsens the paint by mixing it with marble dust.
- More examples
- The tone of his voice has coarsened and his singing lacks the elegant finesse he once possessed.
- The voice tends to coarsen when under pressure in higher registers.
- The facade of the house has lost its render, exposing stones coarsened by age.
- Sun and time coarsen the skin.