marshmallow  
noun uk/ˌmɑːʃˈmæl.əʊ/ us/ˈmɑːrʃˌmæl.oʊ/
  (SWEET)      
  [ C or U ]棉花软糖 
a soft, sweet, pink or white food
  Why don't we toast some marshmallows over the fire? 何不在火上烤些棉花软糖呢? 
   (COWARD)      
 [ C ] informal humorous怯懦的人;不自信的人 
a person who is not strong, brave, or confident
  The situation called for someone tough, and I was a complete marshmallow. 这种局面需要一个自信坚定的人,而我太胆小软弱了。