adjective
not well or healthy :sick or unhealthy
usually used after a verb
The comparative form iller and the superlative form illest are sometimes used for this sense.
b of health :not normal or good
always used before a noun :harmful or damaging
always used before a noun :not helpful or lucky
The saying it's an ill wind that blows no good or it's an ill wind that blows nobody (any) good means that something that is bad in most ways is usually also good in some way.
always used before a noun :not kind or friendly
ill repute
with ill grace
adverb
in a bad or imperfect way :badly, poorly
in an unfavorable or unkind way
ill afford
If you can ill afford something, you should not do it or get it because it will cause problems.
noun
plural ills
[noncount] :bad or unlucky things
[count] :a sickness or disease
usually plural
b ills [plural] :troubles or problems