Khuzdul is the language J.R.R. Tolkien created for the Dwarves in his legendarium. It is also called the Dwarvish language and was designed as a language distinct from those of Elves and Men.
Tolkien gave Khuzdul a sound and structure unlike his Elvish languages. The Dwarves guarded it closely, so comparatively little Khuzdul appears in the published narratives. Names such as Khazad-dûm and battle cries such as “Baruk Khazâd!” provide notable examples.
Quenya and Sindarin are Elvish languages, not Dwarvish ones. Adûnaic belongs to the Men of Númenor. These languages can all appear in Tolkien’s wider linguistic history, making precise identification important.