n. 25B6; adjective
she was feeling rather ill : UNWELL, sick, not (very) well, ailing, poorly, sickly, peaky, indisposed, infirm; out of sorts, not oneself, under/below par, bad, in a bad way; bedridden, invalided, on the sick list, valetudinarian; queasy, nauseous, nauseated; Brit. off colour; informal under the weather, laid up, lousy, rough; Brit. informal ropy, grotty; Austral./NZ informal crook; Brit. informal, dated queer.
the ill effects of smoking : HARMFUL, damaging, detrimental, deleterious, adverse, injurious, hurtful, destructive, pernicious, dangerous; unhealthy, unwholesome, poisonous, noxious; poetic/literary malefic, maleficent, nocuous; archaic baneful.
ill feeling : HOSTILE, antagonistic, acrimonious, inimical, antipathetic; unfriendly, unsympathetic; resentful, spiteful, malicious, vindictive, malevolent, bitter.
an ill omen : UNLUCKY, adverse, unfavourable, unfortunate, unpropitious, inauspicious, unpromising, infelicitous, ominous, sinister; poetic/literary direful.
ill manners : RUDE, discourteous, impolite; impertinent, insolent, impudent, uncivil, disrespectful; informal ignorant.
ill management : BAD, poor, unsatisfactory, incompetent, deficient, defective, inexpert.
well, healthy, beneficial, auspicious, polite.
25B6; noun
the ills of society : PROBLEMS, troubles, difficulties, misfortunes, trials, tribulations; worries, anxieties, concerns; informal headaches, hassles.
he wished them no ill : HARM, hurt, injury, damage, pain, trouble, misfortune, suffering, distress.
the body's ills : ILLNESSES, ailments, disorders, complaints, afflictions, sicknesses, diseases, maladies, infirmities.
25B6; adverb
such behaviour ill became the king : POORLY, badly, imperfectly.
the look on her face boded ill : UNFAVOURABLY, adversely, badly, inauspiciously.
he can ill afford the loss of income : BARELY, scarcely, hardly, only just, just possibly.
things are going ill : BADLY, adversely, unsuccessfully, unfavourably; unfortunately, unluckily, inauspiciously.
we are ill prepared : INADEQUATELY, unsatisfactorily, insufficiently, imperfectly, poorly, badly.
well, auspiciously, satisfactorily.
25A0; ill at ease AWKWARD, uneasy, uncomfortable, embarrassed, self-conscious, out of place, inhibited, gauche; restless, restive, fidgety, discomfited, worried, anxious, on edge, edgy, nervous, tense; informal twitchy, jittery; N. Amer. informal discombobulated, antsy.
25A0; speak ill of DENIGRATE, disparage, criticize, be critical of, speak badly of, be malicious about, blacken the name of, run down, insult, abuse, attack, revile, malign, vilify; N. Amer. slur; informal bad-mouth, bitch about, pull to pieces; Brit. informal rubbish, slate, slag off; formal derogate; rare asperse.