(使)变粗糙
Roughen \Rough"en\, v. t. [imp. & p. p. {Roughened}; p. pr. & vb. n. {Roughening}.] [From {Rough}.] To make rough. Roughen \Rough"en\, v. i. To grow or become rough.
roughen v : make rough or rougher; "rough the surfaces so they will stick to each other" [ant: {smooth}]