Showing no concern, attention, or regard
Lacking or marked by a lack of care
This was a heedless piece of chivalry on Edward's part.
But such Cassandras prophesied to heedless ears.
But that man, so heedless of his words, did not once during the whole time of his activity utter one word inconsistent with the single aim toward which he moved throughout the whole war.
But the world goes on in its life, heedless of the demands of virtue.
To injure Spain and heedless of England's need, Paul IV.