ironclad
adj 1: inflexibly entrenched and unchangeable; "brassbound
traditions"; "brassbound party loyalists"; "an
ironclad rule" [syn: brassbound]
2: without flaws or loopholes; "an ironclad contract"; "a
watertight alibi"; "a bulletproof argument" [syn: unassailable,
unshakable, watertight, bulletproof]