step in

• n. short underpants for women or children (usually used in the plural)

  同义词： pantie panty scanty step-in

• v.
  • get involved, so as to alter or hinder an action, or through force or threat of force

    同义词： intervene interfere interpose

  • act as a substitute

    同义词： substitute deputize deputise

以上来源于: WordNet