As I recall, there are two degrees. Forgivable and Unforgivable

1. Forgivable sins are any conscience acts that are not driven by faith in Christ:

Rom 14:23 "But he who doubts is condemned if he eats, because his eating is not from faith; and whatever is not from faith is sin." NASU


2. The one unforgivalbe sin is blasphemy against the Spirit

Matt 12:31-32 "Therefore I say to you, any sin and blasphemy shall be forgiven people, but blasphemy against the Spirit shall not be forgiven. 32 "Whoever speaks a word against the Son of Man, it shall be forgiven him; but whoever speaks against the Holy Spirit, it shall not be forgiven him, either in this age or in the age to come."
NASU