Definitions of difficulty:

• noun:   the quality of being difficult

  Example: "They agreed about the difficulty of the climb"

• noun:   a factor causing trouble in achieving a positive result or tending to produce a negative result
• noun:   a condition or state of affairs almost beyond one's ability to deal with and requiring great effort to bear or overcome
• noun:   an effort that is inconvenient

  Example: "Had difficulty walking"