mischievous             
adjective uk/ˈmɪs.tʃɪ.vəs/ us/ˈmɪs.tʃə.vəs/
 (人、行为等)爱恶作剧的,好捣乱的,顽皮的,淘气的
behaving in a way, or describing behaviour, that is slightly bad but is not intended to cause serious harm or damage
  She has a mischievous sense of humour. 她很幽默,喜欢搞点恶作剧。 
 a book about the mischievous antics of his ten-year-old daughter 一本有关他10岁女儿顽皮行为的书 
  恶意的
expressing or suggesting mischief
  a mischievous grin 不怀好意的狞笑 
  (行为)有害的;(话语)恶意中伤的
used to describe behaviour or words that are intended to cause harm or trouble
  I think these rumours are mischievous. 我认为这些流言是恶意中伤。