problem
(difficulty) A difficulty that has to be resolved or dealt with.
An addiction, other substance use disorder, or comparable psychological challenge.
(schoolwork exercise) A question to be answered, schoolwork exercise.
(puzzling circumstance) A puzzling circumstance.
Objection.
Difficulty in accepting or understanding or refusal to accept or understand.
(climbing) A set of moves required to complete a climb.
(of a person or an animal) Difficult to train or guide; unruly.
Causing a problem; problematic; troublesome.