English
fallible
Fallible comes from Medieval Latin fallibilis ‘liable to err, also deceitful’, and perhaps goes back to Proto-Indo-European *(s)gʷʰh₂el- ‘to stumble’.
- Proto-Indo-Europeanc. 4500–2500 BCE*(s)gʷʰh₂el-1‘to stumble’uncertain
- Proto-Italicc. 1500–700 BCE*falsō1uncertain
- Latinc. 75 BCE–200 CEfallō2as fallere‘to deceive’
- Medieval Latinc. 600–1500fallibilis2‘liable to err, also deceitful’
- Middle Englishc. 1150–1500fallible2
- Englishtodayfallible2
attested reconstructed ? uncertain or disputed deepest recorded ancestor
- 1 Wiktionary, Latin fallo
- 2 Wiktionary, English fallible
Lineage
- Proto-Indo-Europeanc. 4500–2500 BCE*(s)gʷʰh₂el-Wiktionary, Latin fallo‘to stumble’uncertain
- Proto-Italicc. 1500–700 BCE*falsōWiktionary, Latin fallouncertain
- Latinc. 75 BCE–200 CEfallōWiktionary, English fallibleas fallere‘to deceive’
- Medieval Latinc. 600–1500fallibilisWiktionary, English fallible‘liable to err, also deceitful’
- Middle Englishc. 1150–1500fallibleWiktionary, English fallible
- EnglishtodayfallibleWiktionary, English fallible
Linked words
through Proto-Indo-European *(s)gʷʰh₂el- ‘to stumble’
through Proto-Italic *falsō
fail, default, falsely, falsetto, 5 more
through Latin fallō ‘to deceive’
failure, fault, false, faux, fallacy, fallacious, falsify, falsity, 8 more
Today it means
adj Capable of making mistakes or being wrong.
Sources
Sources: Wiktionary, “fallible”; the older steps come from the Wiktionary entry for Latin fallo. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.
Etymograph / Proto-Indo-European *(s)gʷʰh₂el- / fallible