"Form of Blessing"
The name Blessin is commonly a unisex name from the "English" origin.
Blessin is the English word name Blessing with the final g dropped, the way the -ing ending is commonly written to show pronunciation. It is a spelling variant of that name rather than a separate name with its own root or meaning, and the recorded first appearance in US birth records in 1997 fits a recent respelling rather than an older established form.
Blessing means "Consecrated".
The pronunciation of Blessin is BLESS-in.
