I. | ̷ ̷ ̷ ̷| ̷ ̷ noun
Etymology: under (III) + weight
1. : weight below normal, average, or requisite weight : want of weight : the amount of the deficiency ; specifically : the amount by which the actual shipping weight of lumber differs from the standard weight upon which freight charges are computed
2. : the condition of weighing less than the weight normal for an age or height
3. : a person or article whose weight is less than normal or standard
II. adjective
Etymology: under (II) + weight, n.
: weighing less than the normal amount ; especially : below the normal weight for the age