Jadaf جدف: (v. or n.) to blaspheme (the name of God) or blashempy, to revile or reviling, to swear to a lie
Jahannam جهنم: Hell; reference to and description of it has already been made in my book titled Mary and Jesus in Islam. However, if you do not have a copy of it, here is what I wrote in explaining the Hebrew origin of this word: “Ge hen Hinnom,” Hebrew for “the valley of the son of Hinnom.” Jews believe that this valley is a place near Jerusalem where, according to Jeremiah 19:5, [Gentile] children were burnt in sacrifice to Baal.
The latter was the fertility god of then polytheist Canaanites (Arabs, descendants of Ken`an, who inhabited Greater Syria. According to Vol. 1, p. 24 of Civilization: Past and Present, “'Phoenician' is the name which the Greeks gave to those Canaanites who dwelt along the Mediterranean coast of Syria, an area that is today Lebanon.”). The Greeks, then, were the ones who called those Arabs "Phoenicians". Ge hen Hinnom is Arabized as “Jahannam.”
Before the advent of Islam, Arabs believed neither in heaven nor in hell; they had no clear concept of the afterlife. They, therefore, had no words for Paradise or hell in their very rich and extensive vocabulary. “Janna جنة,” by the way, means: a garden, an orchard, but it really does not describe Paradise fully. Paradise is a lot more than an orchard or a garden. It is a whole world by itself. Incidentally, the word “Paradise” (firdaws) is also a loan word, some say from Persian, others from Babylonian.
Jahid جاحد: ingrate, unappreciative, denies favors, denies the existence of the Creator (apostate), atheist
Jahil جاهل: ignorant, illiterate, unlettered
Jahiliyya جاهليه: period of overwhelming ignorance, a reference to the conditions of the Arabs before the advent of Islam. It implies is a combination of views, ideas, and practices that totally defy and reject commonsense and the guidance sent down by God through His Prophets.
Ja’ir جائر: oppressive, unfair, unjust, unequitable, transgressing, encroaching, transgressing
Ja'iz جائز: permissible, allowable, admissible, possible, probable
Jalbab جلباب: long loose fitting garment worn by the Arabs
Jalda or Jaldah جلده: lash, whip
Jallad جلاد: executioner, headsman, hangman
Jami `a جامعه: inclusive, universal, university; it also means handcuffs
Janaba جنابه: uncleanness caused by seminal discharge
Jannat or Jannah جنه: heaven, Paradise, garden, the eternal abode of those with whom the Almighty is pleased; plural: jannaat
Janih جانح: devious, errant, delinquent, misdemeanant
Jami` جامع: mosque, house of congregational worship, same as masjid مسجد; literally, it means "place where people gather for يتجمع prayers"
Janin جنين: fetus
Jard جرد: stock-taking, inventory
Jarrada جرد: stripped one (of property, clothes, etc.), deprived of, despoiled, denuded
Jariya جاريه: bondmaid, slave girl, servant
Jasha` جشع: greed, avarice, avidity; one who is greedy is called jashi` جشع
Jaza'i جزائي: punitive, penal, vindicatory
Jazak Allahu khayran or Jazak Allahu Khairan, Jazak Allah Khair, Jazak Allahu Khair جزاك الله خيرأ: This is a statement of thanks and appreciation said to the person who does a favor. Instead of saying "thanks" (Shukran), the Islamic statement of thanks is to say this phrase. Its meaning is: " May Allah reward you for the good deed which you have done." It is understood that human beings can't repay one another enough, especially and particularly his parents and educators. Hence, it is better to plead to the Almighty, Allah, to reward the person who did you a favor to grant him what is best for him.
Jawhara جوهره: jewel, precious (stone, etc.)
Jazim جازم: positive, sure, categorical
Jidal جدال: arguing, argument, debate, discussion
Jihad or Jihaad جهاد: It is an Arabic word the root of which is "jahada" which implies one who has strived for a worthy cause, a better way of life, etc. The nouns from which the word is derived are: juhd (effort, endeavor, exertion, exhaustion), mujahid (one who exerts himself or defends the creed, provided such defense is not done through aggression or through any means not allowed by Islam), jihad (struggle, defense of the Islamic creed) and ijtihad (ultimate effort in order to derive a solution for a problem related to jurisprudence; one who does so is called mujtahid, a highly learned jurist capable of deriving Islamic rulings). The other meanings are: strain, exertion, effort, diligence, fighting to defend one's life, land and religion. Jihad has commonly been mis-translated or misrepresented to the world to mean "holy war".
In the absence of the Prophet, such a war does not exist in Islam, nor will Islam allow its followers to be involved in this so-called "holy war". Unfortunately, the past few years have witnessed the rising of a number of extremist movements that justify the shedding of the blood not only of non-Muslims but even of Muslims who do not agree with their ideologies. Those who are hostile to Islam have utilized the acts of terrorism committed by these groups, mostly identified as Takfiri groups, groups that label all others as "kafirs", apostates, to tarnish Islam's image. They use Islam as a pretext for their criminal acts just as the crusaders had done during the Middle Ages when even some crusaders shed the blood of their own Christian brethren.
Jihad is not a war to force the Islamic faith on others, as many ignorant people think or portray. Contrariwise, there is an explicit verse in the Qur'an that says the following:
"There is no compulsion in religion" (Chapter Al-Baqarah, 2: 256).
Jihad is not only a defensive war but a struggle, through peaceful means, against any unjust regime or any injustice, period. If such a regime exists—and there are many which do exist—such an effort has to be exerted against the leaders, the decision-makers, not against the people. Islam strongly prohibits terrorism, kidnapping, hijacking and depriving one of his freedom, even if this "one" is an animal or a bird. One statement made by the Prophet of Islam (ص) says, "A woman entered hell because of a cat which she confined, neither feeding it nor letting it eat of what is available on the ground."
As for some "Muslim" political figures, leaders and rulers who waged wars against non-Muslims in the pretext of "spreading Islam", they were further from Islam than the earth is from the sun and did what they did for political, economic or selfish reasons. They were ignorant of the true message of Islam. Unfortunately, there are many such "Muslims" in our time and in all times and climes.
Jinaya or Jinayah جنايه: serious crime, felony
Jinn or Jin, Ginn جن: These are spiritual beings, “genies”, that inhabit the world and, like humans, are required to follow the commandments of their Creator. They are held accountable for their deeds. Some of them are good while most of them are not, as is the case with humans. The meaning of the word "jinn" in Arabic is "hidden", invisible, because they cannot be seen by most humans. They were created by the Almighty from smokeless fire. I discussed the jinns in more detail in my book titled Allah: The Concept of God in Islam.
Jirab جراب: pouch, bag, sack
Jizya or Jizyah جزيه: tribute, protection tax paid to Muslims by non-Muslims residing in areas under Islamic control. The Muslims collect this tax in exchange for protecting the lives and possessions of these non-Muslims, exempting them from the military service and awarding them full freedom to practice their religion, whatever it may be.
If the Islamic State cannot protect those who have paid the jizya, they are entitled to get it back. In all reality, such tax is hardly collected because even in Pakistan, where the majority are Muslims living with mostly Hindu and Buddhist minorities, the latter do not pay any jizya.
Jumood جمود: stagnation, freezing, inaction, inactivity, passiveness (to influence, change, etc.)
Junha or Junhah جنحه: misdemeanor
Junoon or Jinoon جنون: madness, insanity
Jutham جذام: leprosy
Juzaf جزاف: at random, haphazard, casual