What is difference between malnutrition and undernutrition?

Malnutrition arises from deficiencies of specific nutrients or from diets based on inappropriate combinations or proportions of foods; for example, goitre, scurvy, anaemia and xerophthalmia are forms of malnutrition caused by inadequate iodine, vitamin C, iron and vitamin A, respectively. Malnutrition can also result from excess nutrient losses or utilization.

Undernutrition is caused primarily by an inadequate intake of dietary energy, regardless of whether any other specific nutrient is a limiting factor.