difficulty-n; 3 Senses

Sense Number 1: effort

Commentary: an effort that is inconvenient

He had difficulty walking.
She finished the test with great difficulty.

WordNet 2.0 Sense Numbers: 1

Sense Number 2: troubles

Commentary: DIFFICULTY[+event] a factor causing trouble in achieving a positive result or tending to produce a negative result

Serious difficulties were encountered in obtaining a pure reagent.
Their financial difficulties lasted six months.
Those difficulties could've been prevented with proper preparations.
The car accident, the house fire, and his broken foot were just three of the difficulties he attributed to his superstitions.

WordNet 2.0 Sense Numbers: 2 3

Sense Number 3: difficultness

Commentary: the quality of being difficult

They agreed about the difficulty of the climb.

WordNet 2.0 Sense Numbers: 4