(literary) urgently; anxiously; earnestly
Originally a pictograph of a person with lines at the top and bottom, depicting the original meaning "extremity". Later the 口 (mouth) and 又 (hand) components were added to depict shouting in an urgent situation, such as being chased.
《說文》：“亟，敏疾也。从人，从口，从又，从二。二，天地也。”