un ‧ bridge ‧ a ‧ ble /ʌnˈbrɪdʒəb ə l/ BrE AmE adjective
unbridgeable differences between two people, groups, or ideas are so big that no one will ever agree about them or be satisfied with them
unbridgeable gulf/gap/chasm etc (between somebody/something and somebody/something)
the unbridgeable gulf between the rich and the poor