I. -ˈklad adjective
Date: circa 1847
1. : sheathed in iron armor — used especially of naval vessels
2. : so firm or secure as to be unbreakable: as
a. : binding
an ironclad oath
b. : having no obvious weakness
an ironclad case against the defendant
II. -ˌklad noun
Date: 1862
: an armored naval vessel especially of the mid to late 19th century