dust and dirt; 尘垢
dental calculus; 牙垢
silently endure humiliation and insult 含垢忍辱
pipe scale 管垢
shelter evil people and countenance evil practices 藏污纳垢
with dishevelled [unkempt] hair and a dirty [an unwashed] face 蓬头垢面
牛津高阶第八版
美国韦氏词典
Dictionary.com
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维基百科 (自由的百科全书)