

Она сегодня больная и не придёт.
She's sick today and won't come.
У меня больная спина.
I have a bad back.
У него дома больная мама.
He has a sick mother at home.
"больная" is in the lesson "Treatment" (Level 13), along with 14 other useful words. LinDuo has 180 topic lessons like this one, 2,380 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.