@alex fwiw, I've never heard that word used, though I would understand it in context.

Compared to a few synonyms: https://books.google.com/ngrams/graph?content=reckless%2Coverbold%2Cnegligent%2Cheedless%2Coverconfident&year_start=1800&year_end=2022&corpus=en&smoothing=3

I think "heedless" is the closest I can come up with as a regularly used word