adjective

suffering from an illness or disease or feeling unwell.

he was taken ill with food poisoning

unwell,sick,not (very) well,ailing,poorly,sickly,peaky,afflicted,indisposed,infirm,liverish,out of sorts,not oneself,not in good shape,not up to par,under/below par,bad,in a bad way,bedridden,invalided,on the sick list,valetudinarian,queasy,nauseous,nauseated,weak,feeble,frail,diseased,infected,off colour,under the weather,not up to snuff,laid up,funny,peculiar,iffy,crummy,lousy,rough,groggy,green around the gills,at death’s door,like death warmed up,ropy,grotty,dicky,wabbit,crook,queer,seedy,crappy

adverb

badly, wrongly, or imperfectly.

the street is dominated by ill-lit shops

poorly,badly,imperfectly,wrongly,unsuccessfully,adversely,unfavourably,unfortunately,unluckily,hard,inauspiciously,inadequately,unsatisfactorily,insufficiently,deficiently,defectively,negligently

noun

a problem or misfortune.

a lengthy work on the ills of society

problems,troubles,difficulties,misfortunes,strains,trials,tribulations,trials and tribulations,worries,anxieties,concerns,pain,suffering,hardship,misery,woe,affliction,distress,disquiet,malaise,headaches,probs,hassles,travails,illnesses,ill/poor health,ailments,disorders,complaints,afflictions,sicknesses,diseases,maladies,infirmities,indispositions,infections,contagions