falter

An unsteadiness.

Tom, who isn't paying much attention, is suddenly caught by the falter in his voice as he reads the two lines—

To waver or be unsteady; to weaken or trail off.

He found his legs falter.

Considering the results of the study, today John may be buoyed at the clear trend of increasing numbers of new “lishes” for each successive decade since the 1950s, and the fact that nothing in the data suggests this trend is likely to falter.

To stammer; to utter with hesitation, or in a weak and trembling manner.

And here he faltered forth his last farewell.

With faltering speech and visage incomposed.

To fail in distinctness or regularity of exercise; said of the mind or of thought.

Here indeed the power of distinctly conceiving of space and distance falters.

To stumble.

To lose faith or vigor; to doubt or abandon (a cause).

And remember, comrades, your resolution must never falter.

The most important foreign policy problem I faced was that of signaling to the world what kind of man I was and what sort of policies I intended to carry out. It was important that there be no hesitancy on my part — nothing to indicate that the U.S. government had faltered. It was equally important for the world to understand that I intended to continue the government's established foreign policies and maintain the alliances of Harry S. Truman, Dwight D. Eisenhower, and John F. Kennedy — policies of firmness on the one hand and an effort to thaw the Cold War on the other.