A lack of attention; inability to concentrate because the mind is distracted.
授業中にスマホを見ていて注意散漫になった。
I was looking at my phone during class and became distracted.
注意散漫が原因でミスが増えた。
Mistakes increased due to inattention.
注意散漫は集中力トレーニングで改善できることが多い。
Inattention can often be improved with concentration training.