Main entry: unassailable, bulletproof, unshakable, watertight
Definition: without flaws or loopholes
Usage: an ironclad contract; a watertight alibi; a bulletproof argument
Main entry: unbendable, unfaltering, steadfast, steady, stiff, unshakable, unwavering, firm
Definition: marked by firm determination or resolution; not shakable
Usage: firm convictions; a firm mouth; steadfast resolve; a man of unbendable perseverence; unwavering loyalty