setback · reverse · check · defeat · frustration · disappointment · to frustrate · to discourage · to set sb back · to blunt · to subdue

There will be setbacks and false starts. There are many who won't agree with every decision or policy I make as president. And we know the government can't solve every problem.

How frustrated must a person be to commit suicide?

There's an upside to everything so it's unnecessary to focus on the good; on the contrary, we should instead be pushing for reversals because it's only through setbacks that we improve and see decisive opportunities clearly.

He overcame all sorts of hardship and setbacks to succeed in a solo crossing of Antarctica.