(verb)
to speak hastily or incoherently and often in bursts, due to some strong emotion such as excitement or confusion;
e.g. He could only sputter in rage, being too angry to form complete sentences.
(verb)
to occur in a feeble or erratic way (in short bursts), often accompanied by popping or explosive noises;
e.g. The car began to jolt and sputter to a halt.
(verb)
in physics, to deposit metal ions onto a surface in order to coat the surface using a spray of fast and high-energy ions or particles;
e.g. They plan to sputter the sheet with zinc to form a protective coating.
(noun)
a soft explosive or popping sound, a series of such sounds, or the action of making such sounds;
e.g. The engine gave a sputter before shutting off.
(noun)
speech or discussion that is excited and/or confused;
e.g. I heard the sputter of voices in the room.