adverb (r)

• with no problems or difficulties(adv.all)

  Example:
  Put the plans into effect quickly and smoothly.
  

  Synonym:
  swimmingly
  

  source: wordnet30
• in a smooth and diplomatic manner(adv.all)

  Example:
  `And now,' he said smoothly, `we will continue the conversation'.
  

  source: wordnet30
• In a smooth manner.(adverb)

  source: webster1913