inconsideration
Lack of due consideration; inattention to consequences, thoughtlessness.
countable, uncountable
new trained Souldiers, and such as are but novices in the trade, doe often headlong, and hand over head cast themselves into dangers, with more inconsideration, than afterward when they have seene and endured the first shocke, and are better trained in the schoole of perils.
Where it comes from
Borrowed from Middle French inconsideration and its source, Latin incōnsiderātiōnem.
Adapted from the Wiktionary entry inconsideration (CC BY-SA 4.0).