איוב ג:ח פירוש: רש״י

curse it Heb. יקבהו, curse it, as in (Num. 22:17), “curse (קבה) for me.”

those who curse the day Those who curse their days, since they intend to pronounce a curse because of their anguish.

those destined to be childless in their union Heb. ערר לויתן, to be childless (ערירים) in their union; to join their mate in the union of man and wife, without children. And I saw in the Jerusalem Talmud (Moed Katan 1:5) that עֹרֵר means, to lament their mate when he dies, as in (Moed Katan 1:6): A person may not inspire lamentations (יערער) for his dead relative.