| Noun | 1. | avitaminosis - any of several diseases caused by deficiency of one or more vitaminsberiberi - avitaminosis caused by lack of thiamine (vitamin B1) malnutrition - a state of poor nutrition; can result from insufficient or excessive or unbalanced diet or from inability to absorb foods rickets, rachitis - childhood disease caused by deficiency of vitamin D and sunlight associated with impaired metabolism of calcium and phosphorus scorbutus, scurvy - a condition caused by deficiency of ascorbic acid (vitamin C) | |