We don't have synonyms for ironside yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are inside, ironlike and ironhide.
(n) :
(historical) A trooper in the Parliamentarian cavalry formed by English political leader Oliver Cromwell in the 17th century, during the English Civil War.
(n) :
(historical) A trooper in the Parliamentarian cavalry formed by English political leader Oliver Cromwell in the 17th century, during the English Civil War.