shackly

Probably from dialectal shackle (“to shake, rattle”) +‎ -y.

shackly (comparative more shackly, superlative most shackly)

1. (UK, US, colloquial, dated) Shaky, rickety, ramshackle.
   • 1876, Mark Twain, The Adventures of Tom Sawyer, page 228:

     when I got to that old shackly brick store by the Temperance Tavern, I backed up agin the wall to have another think.

2. (dialectal) Loose-jointed, shambling.

• ackshly