The Omniscient Witness, The Certifier, The Testifier
The One who directly and ever-presently observes everything in creation. The One from whose knowledge nothing is hidden.
The One who witnesses both that which is seen and that which is unseen. The One who has knowledge of all that happens everywhere at all times.
The One who is the ultimate witness on judgment
From the root sh-h-d which has the following classical Arabic connotations:
This name is used in the Qur'ān. For example, see 85:9
(Also written as al-shahid, al-shaheed, ash-shahid, ash-shaheed, the Testifier: ya shahid, ya shaheed)