mole  
noun [ C ] uk/məʊl/ us/moʊl/
  (ANIMAL)     
  鼹鼠
a small mammal that is almost blind, has dark fur, and lives in passages that it digs underground
   (SPOT)      
  痣
a small, dark spot or lump (= raised area) on a person's skin
 Compare: freckle
   (PERSON)      
  内奸
a person who works for an organization or government and secretly gives information to its competitor or enemy
  A mole inside the Department had leaked secret proposals to the press. 该部门的一名内部人士向媒体泄露了秘密计划。 
 Compare: spy noun
   (MEASUREMENT)     
 chemistry specialized摩尔 
a unit of measurement of the amount of a substance expressed in grams