A difficulty that has to be resolved or dealt with.
A puzzling circumstance.
A set of moves required to complete a climb.
A question to be answered, schoolwork exercise.
Objection.
Difficulty in accepting or understanding or refusal to accept or understand.
Causing a problem; problematic; troublesome.
Difficult to train or guide; unruly.
An answer to a problem.
A homogeneous mixture, which may be liquid, gas or solid, formed by dissolving one or more substances.
An act, plan or other means, used or proposed, to solve a problem.
A product, service or suite thereof, especially software.
The act of dissolving, especially of a solid by a fluid; dissolution.
To treat with a solution.