A predator was a hunting lifeform focused on other lifeforms, called prey. Species maps including predators might just consist of a predator-prey binary, or might be more complex food chains.
Species evolved from predators (which included Vulcans, Humans, Betazoids and Ocampa), had violent instincts. (VOY: "Meld";DIS: "The Vulcan Hello")
After Spock told Trelane that his father was from Vulcan, Trelane asked him if the Vulcans were predatory. (TOS: "The Squire of Gothos")
The Vorta believed that they previously existed as small, timid, ape-like forest dwellers living in hollowed-out trees to avoid predators on their homeworld, of which there were many. (DS9: "Treachery, Faith and the Great River")
While stranded on Goralis III in 2375, Worf killed a large furry mammal, somewhat similar to a wolf, for food. Worf also mentioned the planet having predators that might pose a threat to him. (DS9: "Penumbra")
Captain Jean-Luc Picard compared the Scimitar with a predator following a tactical analysis of its weapon systems. (Star Trek Nemesis)
The Doctor's comments on species evolved from predators in "Meld" are somewhat suggestive of the idea that most if not all Humanoids evolved from them.