As nouns the difference between spartan and gladiator
is that
spartan is a red apple cultivar from British Columbia, Canada while
gladiator is in ancient Rome A person (professional or slave) who entertained the public by engaging in mortal combat with another, or with a wild animal.
As an adjective spartan
is austere, frugal, characterized by self-denial.
As a proper noun Spartan
is a citizen of Sparta.