Select the most appropriate one-word substitution for the given group of words.

The time in life in which a person is old and weak

Dotage

The most appropriate one-word substitution for "the time in life in which a person is old and weak" is dotage.

• Dotage is the period of life in which a person is old and weak, and may behave in a foolish or childish manner.
• Senile means showing a decline or deterioration of physical strength or mental functioning, especially short-term memory and alertness, as a result of old age or disease.
• Dyke is a wall or embankment built to prevent flooding.
• Jaunt is a short trip or excursion.