In obsolete terms the difference between then and polite
is that
then is at the time that; when while
polite is smooth, polished, burnished.
As adjectives the difference between then and polite
is that
then is being so at that time while
polite is well-mannered, civilized.
As an adverb then
is at that time.
As a noun then
is that time.
As a conjunction then
is obsolete spelling of lang=en.
As a verb polite is
to polish; to refine; to render polite.