A simple answer to your respondent would be "hogwash", but I suppose we should go into the details. What irritates me is when people who are used to dealing with others who don't have degrees in Greek use their insufficient knowledge as a sort of sledge hammer to "settle" all arguments:
1) Transliterated the word would be
kecharitomene, but anyone dealing with Greek would describe it as what it is, a participle of the verb
charitoo.
2) Of all Indo-European languages of which I am aware, Greek is the most root-focused. The import of that fact here is that the word "grace" or "favor" which is at the root of
charitoo is the key to discovering what that verb means or might mean. To put the matter in terms of its essential accidence,
charitoo is merely a factitive verb, that is, it's what someone does when they want to take a noun and turn it into a transitive verb. Therefore, by its structure and root the verb ought to mean "to give or bestow grace/favor to or on someone". In the case of a perfect participle in passive voice (such as we have here), the form would then mean "someone who has had grace/favor given/bestowed to/on them.
3) To call this word a "hapax" in an attempt to bestow some sort of uniqueness on it is disingenuous. Not only does this verb occur throughout Greek literature - it also occurs
in the Bible at Ephesians 1:6:
Having foreordained us for adoption to Himself through Jesus Christ according to the good pleasure of His will, for the purpose of producing (at salvation) praise for the glory of His grace which He has graciously bestowed on us in the Beloved [One]. Ephesians 1:5-6
So, here the same verb is used in this Ephesian passage. So....were the Ephesians graced with all possible grace, making them without sin?