This is the 793rd most frequent Danish word.
dårlig
Bad.
In this sentence, 'dårlig' is used as an adjective to describe 'idé' (idea), meaning 'bad' or 'not good'.
Det er en dårlig idé at tage ud i regnvejr uden paraply.
It's a bad idea to go out in the rain without an umbrella.
Here, 'dårlig' describes the state of the food, indicating that it is not fresh or has an unpleasant taste.
Maden smagte dårlig efter den havde stået ude hele dagen.
The food tasted bad after it had been left out all day.
'Dårlig' is used to describe someone's condition, in this case suggesting that the speaker is feeling 'unwell' or 'sick'.