1. 1〔ぼんやり〕
    • うっかり約束を忘れてしまった
    • The appointment slipped my mind./I carelessly [absentmindedly] forgot my appointment.
    • うっかりして駅を3つも乗り過ごしてしまった
    • 「I was daydreaming and [My thoughts were elsewhere and I] was carried three stops beyond my destination.
  1. 2〔不注意〕
    • すりが多いからうっかりできません
    • We must be very careful, because there are a lot of pickpockets around.
    • うっかり兄の本を持ってきてしまった
    • I brought my brother's book by mistake.
    • うっかりして招待状をなくしてしまった
    • I inadvertently misplaced my letter of invitation.
    • うっかり本心をしゃべってしまった
    • In an unguarded moment I revealed my true intentions.
  1. うっかり者「a careless [an absentminded] person