【Unwholesome】 , 【morbid】 ,  【sickly】 ,  【diseased】 ,  【pathological】  apply to what is unhealthy or unhealthful in any of various ways.

【Unwholesome】 is applicable not only to what is not healthy or healthful physically and mentally but also to what is morally corruptive.

【Morbid】 , in the sense of showing the effects of disease, is somewhat old-fashioned. The term is more often descriptive of a physical, emotional, mental, or social condition or of fancies, feelings, or behavior that are abnormal or are a sign of abnormality (as derangement, decadence, or deterioration).

【Sickly】 , more than any of these words, implies the appearance of weakness or wanness characteristic of poor health, or an inherent lack of robustness or virility; it applies not only to persons but to animals and to plants, not only to bodies but to minds and souls, not only to thoughts, feelings, and behavior, but to objective things (as colors, odors, or fights) that suggest the quality or character of a person weakened or wasted by disease.

【Diseased】  applies not only to something (as a part or an organism) that is attacked by disease, but, like  【morbid】 , is often extended to whatever is deranged, disordered, dying, or abnormal.

【Pathological】 is applied to physical, mental, and moral conditions which have their origin in disease or which constitute gross deviations from the usual, expected, or normal, and, by implication, the wholesome.