Ishāra (allusion) is that which, due to the subtlety of its meaning, is not explained verbally by the speaker. (Luma, 414)
The purpose of ishāra is to convey one's intention to another without words. (Hujwīrī, 467)
Ishāra occurs by way of distance, even when there is companionship with another's nearness. (Istilāh, 539)
According to the travelers on the path of Allah, ishāra is permitted either because one is distant or because a stranger is present. Regarding proper conduct in gatherings, some shaykhs have said: "Ishāra is to call out to one who is distant, to expose the ailment." By this, they mean to clarify the occurrence of the malady. For 'ailment' is a disease—which is also our view—and by this, they do not intend the 'cause' as defined in the terminology of the rationalists (ahl al-naẓar, i.e., the theologians). There, the form of the malady is as follows: From the one making the ishāra, the Face of the Real (ḥaqq) in these things has become absent. The claim arises from the one in whom the Face of the Real is absent in things. The claim is identical to the malady. According to the verifiers (muḥaqqiqūn), it is established in existence (wujūd) that there is nothing besides Allah (God), and ishfāq (compassion) is affirmed. If we exist, our existence is only by His existence. (Futūḥāt, 1, 350–351)