indissoluble

a. [ L. indissolubilis: cf. F. indissoluble. See In- not, and Dissoluble, and cf. Indissolvable. ] [ 1913 Webster ]

1. Not dissoluble; not capable of being dissolved, melted, or liquefied; insoluble; as, few substances are indissoluble by heat, but many are indissoluble in water. Boyle. [ 1913 Webster ]

2. Incapable of being rightfully broken or dissolved; perpetually binding or obligatory; firm; stable, as, an indissoluble league or covenant. [ 1913 Webster ]

To the which my duties
Are with a most indissoluble tie
Forever knit. Shak. [ 1913 Webster ]