tantamount

Equivalent in meaning or effect; amounting to the same thing in practical terms, even if being technically distinct.

Every moment might bring the British cruisers in sight,—two important expeditions had already been baffled in that way,—and the absolute certainty, known to all parties alike, that delay, under these circumstances, was tantamount to ruin; […]

[…] expecting the woman to take her attacker into physical custody is tantamount to preventing the arrest. If she could handle him, she probably would not need to call the police in the first place.

To amount to as much; to be equivalent.

[…] and yet this will not tant’amount to an immediate Divine inſtitution for Deacons, and how can it then for Presbyters ?

Something which has the same value or amount (as something else). (attributive use passing into adjective, below)

For end thereof, not despondency but madness : for when Cossey understood that Hobday had called his wife a tantamount, he waited for him outside, and gave him what he called a pair of clippers over the ear.