Ungainly (adjective): 1. a. lacking in smoothness or dexterity: clumsy b. hard to handle: unwieldy 2. having an awkward appearance (Merriam-Webster)
Found on Paragraph 10, Page 263 of “A Jury of Her Peers”–>“The county attorney was looking at the cupboard — a peculiar, ungainly structure, half closet and half cupboard, the upper part of it being built in the wall, and the lower part just the old-fashioned kitchen cupboard.”
I believe the word in this quote means that Mr. Hale (the attorney) found that the Wrights cupboards were crafted poorly, making them fragile looking and awkward in shape and appearance.