In The Scarlet Letter, what explanation does the stranger make to the townsman he speaks with that accounts for his combination of "civilized and savage costume"?
It was a somewhat common practice when Massachusetts was still a burgeoning colony for Native Americans to abduct white settlers and then "redeem" them (or, as we would term it, ransom them) back to their home communities in exchange for money. This man, who will later introduce himself as Roger Chillingworth, but who we learn is actually Hester Prynne's husband, says,
"I have met with grievous mishaps by sea and land, and have been long held in bonds among the heathen-folk, to the southward; and am now brought hither by this Indian, to be redeemed out of my captivity."
Thus, it seems that he was shipwrecked and subsequently captured by natives of the continent, and he has now been brought to Boston by them in order that they might sell him to the other white colonists. It makes sense, then, that he is dressed in a strange combination of his European attire as well as some pieces of native garb (because he has been missing for just about two years), and much of his original clothing would certainly have worn out in that time and with hard use.
The stranger states that he has "met with grievous mishaps by sea and land, and have been long held in bonds among the heathen folk, to the southward; and am now brought hither by this Indian, to be redeemed out of my captivity." In other words, the stranger (Prynne/Chillingsworth) has been shipwrecked or met trouble by ship, had difficulties after reaching land, and been held captive by Indians. He indicates that the Indian he has been traveling with has now brought him back to civilization to be freed.