noun (n)

• vertical space available to allow easy passage under something(noun.quantity)

  Synonym:
  clearance, headroom
  

  source: wordnet30
• forward movement(noun.event)

  Example:
  The ship made little headway against the gale.
  

  Synonym:
  head
  

  source: wordnet30
• The progress made by a ship in motion; hence, progress or success of any kind.(noun)

  source: webster1913