This is the 14934th most frequent German word.
rücksichtslos
Rücksichtslos: Reckless or inconsiderate.
The word 'rücksichtslos' is used to describe his driving behavior, indicating that he is not considering the safety of others while driving.
Er fährt rücksichtslos durch die Stadt.
He drives recklessly through the city.
Here, 'rücksichtlose' is an adjective describing the behavior, implying that the man acted without regard for the feelings or opinions of those present.
Das rücksichtlose Verhalten des Mannes schockierte die Anwesenden.
The inconsiderate behavior of the man shocked the attendees.
In this sentence, 'rücksichtslos' characterizes how she expressed her opinion, suggesting she did so in a manner that ignored or dismissed the potential impact on others.