undissolvable

While he spoke of an undissolvable Union and challenged the constitutionality of secession, he reassured the southern states that they had nothing to fear from his administration.

Edna Greene Medford: How influential was Abraham Lincoln's inaugural speech in keeping the border states in the Union? 2011

But of course the original plan hadn't included two hours in a little white room, two hours of steady questioning from one bunch of Customs agents while another bunch first drained and then raked the contents of Flight 901 's waste-tanks, looking for the big carry they also suspected, the big carry that would be unflushable, undissolvable.

The Drawing of the Three King, Stephen, 1947- 1987

What though we lose a thousand meteors from the sky, if skyey depths, if star-dust and undissolvable nebulae remain?

A Week on the Concord and Merrimack Rivers 1849