The Prophet ﷺ said: “The most beloved of your names to Allah are ʿAbd Allah and ʿAbd al-Rahman” (Muslim 2132), and scholars add to them all names formed on a name of Allah. The name al-Haqq occurs 10 times in the Quran; its page in the 99 Names section gives its meaning and verses.
ʿAbd al-Haqq joins ʿabd with al-Haqq, from the root h-q-q of truth, of what is real and due: the One whose existence is certain and who is Truth itself. The Quran: “Allah is the Truth” (22:6). The name is very common in the Maghreb (Abdelhak) and South Asia (Abdul Haq).
There, [on that Day], every soul will be put to trial for what it did previously, and they will be returned to Allāh, their master, the Truth, and lost from them is whatever they used to invent.