Lit. “One terrible in power.” A title given to the agent of inspiration in the Suratu ‘l-Najm (liii.), verse 5: “Verily the Qur’an is no other than a revelation revealed to him; one terrible in power (shadidu ‘l-quwa) taught it him.”
Commentators are unanimous in assigning this, title to the angel Gabriel.
Based on Hughes, Dictionary of Islam