Definify.com
Webster 1913 Edition
Unsin
Un-sin′
,Verb.
 T.
 [1st pref. 
un- 
+ sin
.] To deprive of sinfulness, as a sin; to make sinless. 
[Obs.] 
Feltham.
 Definition 2025
unsin
unsin
English
Verb
unsin (third-person singular simple present unsins, present participle unsinning, simple past and past participle unsinned)
- (transitive) To undo or annul a past sin.
 -  (obsolete, transitive) To deprive (a sin, etc.) of sinfulness; to make sinless.
- (Can we find and add a quotation of Feltham to this entry?)