In the Holy Quran in addition to other words Maut and Wafaat are used for death.
Maut when used alone may mean accidental death or natural death. Wafaat almost always means natural death.
When used together Maut indicates accidental death and wafaat natural death:
Tawaffa Hunnal mauto (4:16) (also see 32:12; 39:43 and 6:62)
Maut also is used to describe death of other things like passions, earth, kingdoms etc.:
And Allah has sent down water from the sky and quickened therewith the earth after its death. Wallaho anzala minas sama ay maa un fa ahya bayhil arza baada mauteha (16:66) (Also see 34:15)
To put it simply, MAUT is death due to any cause(s) whereas WAFAAT indicates death due to natural, non-violent causes.
Use of Wafaat is very pertinent when used to describe the death of Jesus Christ in the Holy Quran:
When Allah said, ‘O Jesus, I will cause thee to die a natural death and will exalt thee to Myself (Ya Esa inni mutawaffika wa rafay o ka) (3:56)
And when Allah will say, “O Jesus, son of Mary, didst thou say to men, ‘Take me and my mother for two gods beside Allah?’”, he will answer, “Holy art Thou. I could never say that to which I had no right. If I had said it, Thou wouldst have surely known it. Thou knowest what is in my mind, and I know not what is in Thy mind. It is only Thou Who art the Knower of hidden things. (5:117)
“I said nothing to them except that which Thou didst command me — ‘Worship Allah, my Lord and your Lord.’ And I was a witness over them as long as I remained among them, but since Thou didst cause me to die (falama tawaffaytani kunta unta raqeeba) Thou hast been the Watcher over them; and Thou art Witness over all things. (5:118)
Other examples of use of wafaat are:
“Our Lord, we have heard a Crier calling us unto faith, ‘Believe ye in your Lord,’ and we have believed. Our Lord, forgive us, therefore, our errors and remove from us our evils, and in death number us with the righteous. (tawaffana mah al abrar) (3:194)
When the Pharaoh’s magicians had believed in Moses and the Pharaoh threatened to cut off their hands and feet, the magicians prayed as follows: “Our Lord, send down upon us steadfastness and cause us to die in a state of submission. (tawaffana muslemeen)” (7:127)
When the Prophet Joseph was appointed governor of a province in Egypt, he prayed as follows: “Lord, Thou hast bestowed sovereignty upon me and taught me the interpretation of dreams. O Maker of the heavens and the earth, Thou art my protector in this world and the Hereafter. Make me die in a state of submission (tawaffani muslemaun) and join me with the righteous.” (12:102)
Allāhu ʾaʿlam [Allah knows best].
The hidden treasures of knowledge in The Holy Quran are for us to find. May Allah enable us to do so. Aameen.