"ironclad" in the noun sense
1. ironclad
a wooden warship of the 19th century that is plated with iron or steel armor
"ironclad" in the adjective sense
1. ironclad
sheathed in iron plates for protection
2. ironclad, brassbound
inflexibly entrenched and unchangeable
"brassbound traditions"
"brassbound party loyalists"
"an ironclad rule"
Source: WordNet® (An amazing lexical database of English)
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