—adj.
1 (usu. predic.; often foll. by with) out of health; sick (is ill; was taken ill with pneumonia; mentally ill people).
2 (of health) unsound, disordered.
3 wretched, unfavourable (ill fortune; ill luck).
4 harmful (ill effects).
5 hostile, unkind (ill feeling).
6 archaic morally bad.
7 faulty, unskilful (ill taste; ill management).
8 (of manners or conduct) improper.
—adv.
1 badly, wrongly (ill-matched).
2 a imperfectly (ill-provided). b scarcely (can ill afford to do it).
3 unfavourably (it would have gone ill with them).
—n.
1 injury, harm.
2 evil; the opposite of good.
Phrases and idioms:
do an ill turn to harm (a person or a person's interests). ill-advised
1 acting foolishly or imprudently.
2 (of a plan etc.) not well formed or considered. ill-advisedly in a foolish or badly considered manner. ill-affected (foll. by towards) not well disposed. ill-assorted not well matched. ill at ease embarrassed, uneasy. ill-behaved see BEHAVE. ill blood bad feeling; animosity. ill-bred badly brought up; rude. ill breeding bad manners. ill-considered = ill-advised. ill-defined not clearly defined.
ill-disposed
1 (often foll. by towards) unfavourably disposed.
2 disposed to evil; malevolent. ill-equipped (often foll. by to + infin.) not adequately equipped or qualified. ill fame see FAME. ill-fated destined to or bringing bad fortune. ill-favoured (US -favored) unattractive, displeasing, objectionable. ill feeling bad feeling; animosity. ill-founded (of an idea etc.) not well founded; baseless. ill-gotten gained by wicked or unlawful means. ill humour moroseness, irritability. ill-humoured bad-tempered. ill-judged unwise; badly considered. ill-mannered having bad manners; rude. ill nature churlishness, unkindness. ill-natured churlish, unkind. ill-naturedly churlishly. ill-omened attended by bad omens. ill-starred unlucky; destined to failure. ill success partial or complete failure. ill temper moroseness. ill-tempered morose, irritable. ill-timed done or occurring at an inappropriate time. ill-treat (or -use) treat badly; abuse. ill-treatment (or ill use) abuse; bad treatment. ill will bad feeling; animosity. an ill wind an unfavourable or untoward circumstance (with ref. to the proverb it's an ill wind that blows nobody good). speak ill of say something unfavourable about.
Etymology: ME f. ON illr, of unkn. orig.
Useful english dictionary. 2012.