"Hast a hold upon" can also be described using various synonyms such as 'grip', 'cling on', or 'grasp'. These words are used to indicate a tight or firm hold on something or someone. 'Clasp' and 'seize' can also be used to describe the same action. 'Hold onto' is another synonym which means the same thing as 'hast a hold upon'. These words also indicate that a person is holding onto something strongly or desperately. Other synonyms for 'hast a hold upon' include grasp, grip, clench, cling to, latch onto, and anchor, all of which can be used interchangeably to describe the action of holding onto something tightly.