critical >> /ˈkrɪdək(ə)l/
Definition: [adjective] Expressing adverse or disapproving comments or judgments.
Example: he was critical of many U.S. welfare programs
Definition: [adjective] Expressing or involving an analysis of the merits and faults of a work of literature, music, or art.
Example: she never won the critical acclaim she sought
Definition: [adjective] (of a situation or problem) having the potential to become disastrous; at a point of crisis.
Example: the flood waters had not receded, and the situation was still critical
Definition: [adjective] Relating to or denoting a point of transition from one state to another.
Example: if the density is less than a certain critical value the gravitational attraction will be too weak to halt the expansion
Definition: [adjective] (of a nuclear reactor or fuel) maintaining a self-sustaining chain reaction.