The words halal means lawful, allowed or permitted, and haram means unlawful, forbidden or prohibited, and cognate terms from the trilateral roots h-l-l and h-r-m respectively, most often designate these two categories and are of relatively frequent occurrence. The Koranic declaration of lawfulness or unlawfulness are limited to a relatively few areas of the law as later elaborated by the jurists. Apart from denoting lawfulness, the root h-l-l indicates an exit from the ritual state connected with the pilgrimage and re-entry into the profane state (idha halal-tun) (5:2). The most common means for indicating lawfulness in the Koran is to use the causative verb ahalla means to make lawful, usually with God as the subject: "He makes the good things lawful for them" (7:157), but it is sometimes passive (5:1) concerning certain livestock. In one instance it occurs in the first person plural, in an address to the Prophet (33:50). Very occasionally, people are made the subject of this verb, to suggest that they wrongly deem something lawful (9:37), though words derived from h-r-m are more common in such accusations. It should be noted that the intransitive verb halla (to be lawful) occasionally appears in the negative to indicate that something is not lawful (2:230), providing that one's wife ceases to be lawful after divorce. The Koran also employs the adjectives hill and halal to indicate lawfulness (5:5, 8:69) respectively about certain foods.

Words derived from the root h-r-m not only connote God's making something unlawful but also frequently express the idea of sacredness, such as al-shahr al-haram (the sacred month) (2:194) or al-haram (the sacred precinct, where the Kaba is located) (28:57); hurum (persons in the ritual state associated with pilgrimage) (5:1) and hurumat (sacred ordinances) (2:194, 22:30). The h-r-m derived counterpart to ahalla is the causative verb harrama (to make unlawful), and as in the case of the former, God is frequently its subject (2:173). The Koran does not employ an intransitive verb derived from h-r-m, making do instead with the passive of harrama (5:3), and the related passive participle (6:145), the corresponding participial form from ahalla is not found in the Koran. A number of passages use harrama in the first person plural and in most of these God recounts how He had previously made certain things, especially foods, unlawful for the Jews (4:160, 6:146, 16:118, 28:12). The counterpart of the adjective halal is haram, though they only appear together twice (10:59, 16:116). There is no h-r-m derived equivalent to the form hill but in 21:95, the Kufan tradition of variant readings substitutes the word hirm for haram. Later legal theorists paired hill with the non-Koranic term hurma, vide Fakhruddin Razi's Mahsul (1:15).

Certain other terms in the Koran also connote lawfulness and unlawfulness. A number of passages use the word junah (sin): "It is not a sin for you to