Unbeatable (adjective) — لا يُقهر: Impossible to defeat or surpass. Below are 6 words with a similar meaning; the linked ones have full GL Dictionary entries with their meaning in Arabic.
Too strong to be defeated.
Better than all others (British spelling).
Highest in authority, rank or degree.
unsurpassablematchlessunconquerable
Impossible to overcome.
Too great to be overcome.