This word has a similar meaning to its Spanish lookalike, preocupado, but it’s just different enough to be a false friend.

While “preocupado” means worried or concerned, preoccupied means only that you are completely absorbed in whatever you’re doing, almost lost in thought.

I was worried about my test because I hadn’t studied much, but in the end I passed!
I’m concerned about how expensive our phone bill is becoming. We need to save!

Elizabeth was preoccupied in her work, focusing completely on the numbers in the spreadsheet.
Philip has been very preoccupied with cooking Thanksgiving Dinner, so I’m not bothering him.

See, Elizabeth and Philip aren’t worried about what they’re doing: everything’s under control. They just have to give it their undivided attention.

Just like how you should be preoccupied with English!