Use 'undersized' to highlight something is smaller than what people typically expect. She struggled with the undersized apartment after moving from a spacious house.
Pro Tip 2/3
Not Always Negative
Although often seen as a disadvantage, being undersized can suggest agility or cuteness in the right context. The undersized kitten was the most playful of the litter.
Pro Tip 3/3
Physical Description
Use 'undersized' to describe physical objects or people, not abstract concepts. The undersized chair looked odd at the large dining table.