thoughtless

An absent-minded person might seem thoughtless to others.

When we talk about someone being thoughtless, we usually mean that they don't think carefully before acting or saying something. They might do something without thinking about how it will affect others, or they might not even notice when they hurt someone's feelings. It's as if their thoughts aren't really there – they're just doing things on autopilot. For example, someone who constantly forgets their friends' birthdays or doesn't send thank-you notes after visiting them might seem thoughtless to those around them.