What is the meaning of On_the_clock?

Displayed on the dial of a clock (timepiece).

Working at one's job; occupied in some manner during one's hours of remunerated employment.

During one's official working hours; in or into a position of remunerated employment.

Of a taxicab, engaged for hire; displayed numerically as time or fare on the meter of a taxicab.

In the official time remaining in a game or other sporting event.

In the official time expired in a game or other sporting event.

Under scrutiny due to having to make a decision or produce results within a set period of time.

Displayed numerically on the mileage or kilometric gauge.

Remunerated per unit of time.

Source: wiktionary.org