عاقل
ʿĀqil
The person who reasons and by reasoning arrives at knowledge (ʿilm); plural ʿāqilūn.
What it means
ʿĀqil is the active participle of ʿaqala, to reason. It names the person who uses his mind to tie evidence together and so reaches ʿilm, knowledge. The plural is ʿāqilūn. In law the same word has a further sense, since a sane adult who can reason is the person on whom religious duties and legal responsibility rest. The Quran praises those who reason and criticises those who refuse to. It says that the signs of God are plain to a people who use their minds, and it condemns blind adherence to the customs of the ancestors. The ʿāqil is therefore the ideal hearer of revelation.
Often misunderstood as
That the word means merely “clever”, when it describes a mind that is sound and used responsibly.
What the sources say
Jurists treat sound reason (ʿaql) as one of the conditions of legal responsibility: a person who lacks it, as a child or someone insane, is not charged with religious duties.
Term and Arabic as listed in Ismail al Faruqi, Toward Islamic English (International Institute of Islamic Thought, 1995), p. 40, listed as ʿĀQIL. The definition is restated here.