Something to do with purposefully burying one's head in the sand when it comes to the question of just truth of Allah's existence, authority, rulership, and ability to excercise power.
The literal term along with its combined dimensions appears to point to this hypothsesis.
Below are some varying views:
The word kāfir is the active participle of the root K-F-R. As a pre-Islamic term it described farmers burying seeds in the ground. One of its applications in the Quran is also the same meaning as farmer.[17] Since farmers cover the seeds with soil while planting, the word kāfir implies a person who hides or covers. Ideologically, it implies a person who hides or covers the truth. Poets personify the darkness of night as kâfir, perhaps as a survival of pre-Islamic religious or mythological usage.[18] The noun for disbelief,[19] "blasphemy",[20] "impiety"[21] rather than the person who disbelieves, is kufr.
https://en.m.wikipedia.org/wiki/Kafir
The terms: fat liar, fraud, crook, cheat, infidel, bast@rd, likely lad, etc also carry negative connotations, but are usually applicable in just and proper context.
See also:
Fidelity
2.
the degree of exactness with which something is copied or reproduced.
"the 1949 recording provides reasonable fidelity"
synonyms: accuracy, exactness, exactitude, precision, preciseness, correctness, scrupulousness; strictness, closeness, faithfulness, correspondence, literalness, conformity; realism, verisimilitude, veracity, authenticity, naturalism
"the fidelity of the reproduction"
The origins of the word infidel date to the late 15th century, deriving from the French infidèle or Latin īnfidēlis, from in- "not" + fidēlis "faithful" (from fidēs "faith", related to fīdere 'to trust').
The word Dajjaal is taken from the expression Dajjala al-baeer (he smeared the camel) , referring to when they covered itwith tar.The root dajala means to mix. The word dajala is used to mean deliberately confusing matters and being vague and ambiguous,
Dajal:
Dajjāl (Arabic: دجال) is an adjective of Syriac origin.[1] It is also a common Arabic superlative form of the root word dajl meaning "lie" or "deception".[2] Al-Masīḥ ad-Dajjāl, with the definite article al- ("the"), refers to "the deceiving Messiah", a specific end times deceiver. The Dajjāl is an evil being who will seek to fraudulently impersonate the true Messiah.
The name Dajjal also is rooted in an Arabic word dajel, which means "to gold plate" or "to coat in gold". It is derived from word meaning "to mix".
https://en.m.wikipedia.org/wiki/Al-Masih_ad-Dajjal
embodimentDictionary result for embodiment
/ɪmˈbɒdɪmənt/
noun
a tangible or visible form of an idea, quality, or feeling.
"she seemed to be a living embodiment of vitality"
synonyms: personification, incarnation, incorporation, realization, manifestation, expression, representation, actualization, concretization, symbol, symbolization; More
the representation or expression of something in a tangible or visible form.
"it was in Germany alone that his hope seemed capable of embodiment"
synonyms: personification, incarnation, incorporation, realization, manifestation, expression, representation, actualization, concretization, symbol, symbolization; More
الٓر ۚ تِلْكَ ءَايٰتُ الْكِتٰبِ وَقُرْءَانٍ مُّبِينٍ
"Alif, Lam, Ra. These are the verses of the Book and a clear Qur'an."
رُّبَمَا يَوَدُّ الَّذِينَ كَفَرُوا لَوْ كَانُوا مُسْلِمِينَ
"Perhaps those who disbelieve will wish that they had been Muslims."
ذَرْهُمْ يَأْكُلُوا وَيَتَمَتَّعُوا وَيُلْهِهِمُ الْأَمَلُ ۖ فَسَوْفَ يَعْلَمُونَ
"Let them eat and enjoy themselves and be diverted by [false] hope, for they are going to know."
وَمَآ أَهْلَكْنَا مِنْ قَرْيَةٍ إِلَّا وَلَهَا كِتَابٌ مَّعْلُومٌ
"And We did not destroy any city but that for it was a known decree."
مَّا تَسْبِقُ مِنْ أُمَّةٍ أَجَلَهَا وَمَا يَسْتَئْخِرُونَ
"No nation will precede its term, nor will they remain thereafter."
وَقَالُوا يٰٓأَيُّهَا الَّذِى نُزِّلَ عَلَيْهِ الذِّكْرُ إِنَّكَ لَمَجْنُونٌ
"And they say, O you upon whom the message has been sent down, indeed you are mad."
لَّوْ مَا تَأْتِينَا بِالْمَلٰٓئِكَةِ إِنْ كُنْتَ مِنَ الصّٰدِقِينَ
"Why do you not bring us the angels, if you should be among the truthful?"
مَا نُنَزِّلُ الْمَلٰٓئِكَةَ إِلَّا بِالْحَقِّ وَمَا كَانُوٓا إِذًا مُّنْظَرِينَ
"We do not send down the angels except with truth; and the disbelievers would not then be reprieved."
إِنَّا نَحْنُ نَزَّلْنَا الذِّكْرَ وَإِنَّا لَهُۥ لَحٰفِظُونَ
"Indeed, it is We who sent down the Qur'an and indeed, We will be its guardian."
وَلَقَدْ أَرْسَلْنَا مِنْ قَبْلِكَ فِى شِيَعِ الْأَوَّلِينَ
"And We had certainly sent [messengers] before you, [O Muhammad], among the sects of the former peoples."
وَمَا يَأْتِيهِمْ مِّنْ رَّسُولٍ إِلَّا كَانُوا بِهِۦ يَسْتَهْزِءُونَ
"And no messenger would come to them except that they ridiculed him."
كَذٰلِكَ نَسْلُكُهُۥ فِى قُلُوبِ الْمُجْرِمِينَ
"Thus do We insert denial into the hearts of the criminals."
لَا يُؤْمِنُونَ بِهِۦ ۖ وَقَدْ خَلَتْ سُنَّةُ الْأَوَّلِينَ
"They will not believe in it, while there has already occurred the precedent of the former peoples."
وَلَوْ فَتَحْنَا عَلَيْهِمْ بَابًا مِّنَ السَّمَآءِ فَظَلُّوا فِيهِ يَعْرُجُونَ
"And [even] if We opened to them a gate from the heaven and they continued therein to ascend,"
لَقَالُوٓا إِنَّمَا سُكِّرَتْ أَبْصٰرُنَا بَلْ نَحْنُ قَوْمٌ مَّسْحُورُونَ
"They would say, Our eyes have only been dazzled. Rather, we are a people affected by magic."
(QS. Al-Hijr 15: Verses 1-15)
* Via Qur'an English
http://quran-en.com