Meaning of “ill” - Learner’s Dictionary

ill

adverb uk us /ɪl/ formal

badly:

Many of the nurses were ill prepared to deal with such badly burned patients.
can ill afford (to do) sth

If you can ill afford to do something, it is likely to make things difficult for you if you do it:

This is a match United can ill afford to lose.
speak ill of sb formal

to say bad things about someone

(Definition of “ill adverb” from the Cambridge Learner’s Dictionary © Cambridge University Press)