Having been treated badly.

Third-person singular simple present indicative form of ill-use

Poorly informed; ignorant.

(intransitive, idiomatic) To sound artificial or contradictory.

Alternative form of it's an ill wind that blows nobody any good

Alternative form of it's an ill wind that blows nobody any good

(mathematics) A mathematical problem, asking whether a room with mirrored walls can always be illuminated by a single-point light source, allowing for repeated reflection of light off the mirrored walls. It was solved in 1958: there are such rooms that cannot be thus illuminated.

An optical illusion in which parallel lines are made to appear convergent or divergent by means of oblique intersections.

The property of being ill-formed.

Poorly formed. / (linguistics, computing) Not well-formed.