Chewing
A sign about chewing
Chewing was the process of working something in the mouth with the teeth. It could be performed as part of the act of digestion (food), or simply for recreation (chewing gum).
In 1986, inside the Cetacean Institute, there was a sign talking about cetaceans' teeth that said, "They have teeth, but they don't chew." (Star Trek IV: The Voyage Home)
In 2369, Aquiel Uhnari's dog Maura had apparently chewed Geordi La Forge's shoe in a fit of restlessness. When Uhnari chided her for doing so, La Forge noted that at least she was chewing them in pairs. (TNG: "Aquiel")
When Neelix was teaching Seven of Nine about eating in 2374, he instructed her to chew the food, which she did, but she had to be informed of how swallowing worked. (VOY: "The Raven").