ironclad

adj. armored, protected by an iron covering; hard, tough

n. type of warship covered with iron plates

"Ironclad" (and "broadside ironclad") redirects here. For other uses, see Ironclad (disambiguation) An ironclad was a steam-propelled warship of the later 19th century, protected by iron or steel armor plates.The ironclad was developed as a result of the vulnerability of wooden warships to explosive or incendiary shells. The first ironclad battleship, La Gloire, was launched by the French Navy in 1859; she prompted the British Royal Navy to start building ironclads. After the first clashes of ironclads took place during the American Civil War, it became clear that the ironclad had replaced the unarmored line-of-battle ship as the most powerful warship afloat.
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Adjective
1. inflexibly entrenched and unchangeable; "brassbound traditions"; "brassbound party loyalists"; "an ironclad rule"
(synonym) brassbound
(similar) inflexible
2. without flaws or loopholes; "an ironclad contract"; "a watertight alibi"; "a bulletproof argument"
(synonym) unassailable, unshakable, watertight, bulletproof
(similar) incontestable, incontestible

(n.)
A naval vessel having the parts above water covered and protected by iron or steel usually in large plates closely joined and made sufficiently thick and strong to resist heavy shot.
  

(a.)
Rigorous; severe; exacting; as, an ironclad oath or pledge.
  

(a.)
Clad in iron; protected or covered with iron, as a vessel for naval warfare.
  

Synonyms and related words:
armed cap-a-pie, armor-plated, armored, constant, dour, firm, fixed, fundamentalist, hard, hidebound, immovable, immutable, impliable, in armor, in complete steel, in harness, inalterable, inexorable, inflexible, invariable, iron, ironbound, ironhanded, loricate, loricated, mailclad, mailed, muscle-bound, obdurate, obstinate, orthodox, panoplied, procrustean, purist, puristic, puritan, puritanic, relentless, rigid, rigorist, rigoristic, rigorous, rockbound, stiff, straightlaced, straitlaced, stubborn, unalterable, unbending, uncompromising, unmodifiable, unrelenting, unyielding