What do saint and blameless mean?

Answer:

I suspect that the difficulty is understanding the meaning of "blameless." We tend to assume it means "without fault" or "sinless." However, various people are called "blameless," but being human, we know they have sinned. Interestingly, the one person whom we know was without sin (Jesus) was never called "blameless."

"The word translated “blameless” conveys the idea of a life or covenant standing to which no legitimate charge can be attached. It does not teach sinless perfection on earth but the absence of grounds for accusation before God or men" [Topical Lexicon].

Thus, a saint refers to a person who essentially lives a moral life, where people don't readily charge wrongdoing against him. Not without sin, but mature. Not someone who follows the world, but who follows God. Because a saint lives by God's law, he is viewed as an oddity by worldly people. "But a natural man does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them, because they are spiritually appraised" (I Corinthians 2:14). This is why the Greek word for "saint" emphasizes someone or something set apart because of its difference.

"40 hágios – properly, different (unlike), other ("otherness"), holy; for the believer, 40 (hágios) means "likeness of nature with the Lord" because "different from the world."

The fundamental (core) meaning of 40 (hágios) is "different" – thus a temple in the 1st century was hagios ("holy") because different from other buildings (Wm. Barclay). In the NT, 40 /hágios ("holy") has the "technical" meaning "different from the world" because "like the Lord."

[40 (hágios) implies something "set apart" and therefore "different (distinguished/distinct)" – i.e. "other," because special to the Lord.]" [Helps Word Studies]