The story
- Proto-Indo-European*swé?
- Proto-Indo-European*selbʰ-
- Proto-Germanic*selbaz
- Old Englishself
- Old Englishself-
- Middle Englishself-
- Englishself-
- Medieval Latinauthenticō
- Englishauthenticating
- English todayself-authenticating
From self- + authenticating.
Etymology from Wiktionary, CC BY-SA 4.0.