S: (n) obstacle, obstruction (something immaterial that stands in the way and must be circumvented or surmounted) "lack of imagination is an obstacle to one's advancement"; "the poverty of a district is an obstacle to good education"; "the filibuster was a major obstruction to the success of their plan"
S: (n) difficulty (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"
S: (n) cognitive factor (something immaterial (as a circumstance or influence) that contributes to producing a result)