Wiktionary
adamantinely
adv. In an adamantine way.
Usage examples of "adamantinely".
Beyond all that, I had made an adamantinely pitiless commitment to myself - again, standing in that office in the mansion house - that I would use whatever truth I could discover like a hammer, to lay waste all those about me who were vulnerable to its momentous weight, without knowing what fragility might exist even in those I loved.