The lexicographer ṣāḥib has said: Dallehe: His blood was spilled without cause, that is, his blood was shed in vain. Tedellüh: The loss of reason due to passion (hawā). It has been said: Dellehehü'l-hevā (his intellect was taken away by passion), meaning it cast him into ḥayra (bewilderment) and dahsha (dread).
Abū Zayd, in Kitāb al-Ibil, says: al-Dulūl: The she-camel that does not seek her mate or her offspring. The lack of longing for her mate and offspring is called tedellüh. (Ravza, 347)