The term 'undersized animal' can be summarized by two crossword solutions: SCALLYWAG (9 letters) and RUNT (4 letters). A SCALLYWAG is a mischievous person, often a child, who behaves in a naughty or playful way. The term is derived from the Scottish word 'scallawag, ' which means 'RASCAL.' A RUNT is an animal that is smaller than average, usually due to genetic defects or malnutrition. It is also used to describe a person who is small in stature.