VI. A tradition of Amīr al-mu’minīn, peace be upon him, says: If a man has a “ad-daynu’ẓ-ẓanūn” (i.e. doubtful loan) it is his duty to pay zakāt thereon for all the past years when he recovers it.
قال السيد الرضي : فالظَّنُونُ: الذي لا يَعْلَمُ صاحبُهُ أيقبضُه من الذي هو عليه أم لا، فكأنّه الذي يُظَنُّ به، فمرة يرجوه و مرة لا يرجوه. وهذا من أفصح الكلام، وكذلك كلّ أمرٍ تطلبه ولا تدري على أي شيء أنت منه فهو ظَنون،
as-Sayyid ar-Raḍī says: “aẓ-ẓanūn” is the loan about which the lender does not know whether he will be able to recover it from the borrower. He is like the one who hopes as well as loses hope. This is the most eloquent way of expression. In this way everything about which you do not know where you stand would be ẓanūn.
والجد : البئر العادية في الصحراء، والظنون التي لا يعلم هل فيها ماء أم لا.
In the same strain poet al-A‘shā (Maymūn ibn Qays al Wā’ilī [d. 7/629]) says:
The aẓ-ẓanūn well (i.e., the one that may or may not have water) which is also deprived of the rain of the raining clouds cannot be compared to the Euphrates whose waves are rising high and which is pushing away the boat as well as the adept swimmer.
“judd” means the well (situated in a wilderness), while ẓanūn is that about which it is not known whether or not it has water.