Etymology
Advertisement

ironclad (adj.)

1852 of knights, 1861, of warships, American English, from iron (n.) + clad. Figuratively, of contracts, etc., "very rigid or strict, allowing no evasion or escape," from 1884. As a noun meaning "iron-clad ship," it is attested from 1862.

Advertisement
Advertisement
Definitions of ironclad
1
ironclad (adj.)
sheathed in iron plates for protection;
ironclad (adj.)
inflexibly entrenched and unchangeable;
an ironclad rule
Synonyms: brassbound
2
ironclad (n.)
a wooden warship of the 19th century that is plated with iron or steel armor;
From wordnet.princeton.edu