Ill-lit is a term used to describe a situation or environment that is poorly lit. It is often used to refer to a room, street, or other area that is not adequately illuminated. DIM is a synonym for ill-lit, meaning that it is not brightly lit. DIM lighting can be caused by a lack of natural or artificial light sources, or by the use of low wattage bulbs. Poorly lit areas can be dangerous and can lead to accidents or injuries.