inattentive
Not paying attention or staying focused on something important.
Inattentive means not paying attention or not focusing carefully on what you're doing or what's happening around you. When you're inattentive during a math lesson, your mind might wander to thinking about recess or what's for lunch, and you miss the teacher explaining how to solve a problem. An inattentive driver might not notice a stop sign because they're distracted by something else.
Being inattentive is different from deliberately ignoring something. An inattentive student isn't trying to be rude; they're just having trouble keeping their mind focused on the task at hand. Maybe they're tired, or the material is difficult, or something else is on their mind. We all become inattentive sometimes, especially when we're bored, worried, or exhausted.
The opposite of inattentive is attentive, which means alert and focused. If a friend complains that you've been inattentive to their feelings lately, they mean you haven't been noticing or thinking about what matters to them. When something important is happening, like receiving instructions for a group project or listening to a friend tell you about their day, being inattentive can cause real problems and hurt feelings.