Real Dictionary

badly
If someone behaves badly or treats other people badly, they act in an unkind, unpleasant, or unacceptable way.
If someone or something is badly hurt or badly affected, they are severely hurt or affected.
If something is done badly or goes badly, it is not very successful or effective.
If you want or need something badly, you want or need it very much.

badly in American English
in a bad manner; harmfully, unpleasantly, incorrectly, wickedly, etc.
adjective: in ill health; sick
adverb: in a defective, incorrect, or undesirable way