ironclad

English Thesaurus

1. a wooden warship of the 19th century that is plated with iron or steel armor (noun.artifact)

hypernym	:	combat ship, war vessel, warship,
definition	:	a government ship that is available for waging war (noun.artifact)

2. inflexibly entrenched and unchangeable (adj.all)

similar	:	inflexible,
definition	:	incapable of change (adj.all)

3. sheathed in iron plates for protection (adj.all)

similar	:	sheathed,
definition	:	enclosed in a protective covering; sometimes used in combination (adj.all)