23rd Saturday of 2021.
on the 23rd week of 2021 (using US standard week number calculation).
An apoplectic fit. The OED defines apoplexy: A malady, very sudden in its attack, which arrests more or less completely the powers of sense and motion; it is usually caused by an effusion of blood or serum in the brain, and preceded by giddiness, partial loss of muscular power, etc.