Synonyms and related words :
chip-proof, coherent, cohesive, firm, firm as Gibraltar, fractureproof, impartible, indiscerptible, indissoluble, indissolvable, indivisible, infusible, inseparable, insoluble, made of iron, nonbreakable, rigid, shatterproof, solid, sound, stable, staunch, stout, sturdy, unbreakable, undividable, unified, unshatterable