uncollapsible

un- +‎ collapsible

uncollapsible (not comparable)

1. Not collapsible.
   • 1897, Guy Boothby, chapter 3, in The Beautiful White Devil‎:

     She carried six boats, an unusually large number for a craft of her size; two were surf-boats, I found on inspection; two were uncollapsible lifeboats; one was an ordinary ship's gig, while the other was a small steam launch of excellent build and workmanship.

   • 1944, Emily Carr, “The House of All Sorts”, in Furniture‎:

     The dining-table, uncollapsible and highly varnished, the piano, the chesterfield, stuffed chairs and a few sofas made a foundation on which to heap lesser articles.

   • 2004, Philip Roth, chapter 4, in The Plot Against America, Houghton Mifflin, page 130:

     Alvin’s wheelchair went into the trunk, though as it was the old unwieldy uncollapsible type, the lid of the trunk had to be tied shut with heavy twine to accommodate it.