There are several synonyms for the phrase "cut off short," which means to stop something suddenly or abruptly. One alternative is "abruptly terminate," which implies a sudden and unexpected cessation. Another option is "curtail," which connotes a reduction in length or duration. "End abruptly" is another equivalent phrase that implies a sudden and unceremonious conclusion. "Halt" is also an appropriate synonym, implying a sudden cessation or interruption. Finally, "cease abruptly" suggests an unexpected and sudden termination of something. Each of these phrases can be used interchangeably with "cut off short" to convey a sudden and unexpected halt to an action.