na-adjective, noun
Describes a person or thing that is physically small in stature or dimensions. Often used for people, animals, or objects.
彼女は小作りだが、とても元気だ。
She is small in build, but very energetic.
この犬は小作りで、室内で飼いやすい。
This dog is small-sized and easy to keep indoors.
小柄 also means 'small build' but is more common and specifically refers to a person's petite frame. 小作り is less frequent and can apply to objects as well.
Compound of 小 (small) and 作り (making/build). The exact historical derivation is uncertain, but it literally suggests something made in a small way.