English Reference
Adverb

erroneously

adv. manner
C1 Advanced US /ɛˈɹoʊniəsɫi/ UK /ɛɹˈəʊniəsli/ er·ro·neous·ly

adv.in a way that is wrong or based on a mistake.

adv.in a mistaken or incorrect manner; based on an error in fact or logic.


SIMPLE

The computer erroneously flagged the file as a virus.

CONTEXTUAL

The bank erroneously credited her account with an extra thousand dollars due to a software glitch.

COMPLEX

Historians once erroneously believed the ruins dated back to the Bronze Age, but modern carbon dating has since corrected that timeline to the medieval period.

Usage

Typically placed before the verb it modifies or at the end of the clause.

Pitfall
The data was erroneously.The data was erroneous.

Learners often use the adverb 'erroneously' when the adjective 'erroneous' is required after a linking verb like 'be'.

An earlier version erroneously included a release date for the game, but none has yet been announced.

The Guardian· 20 Aug 2026

Kennedy Jr., often claim erroneously that children’s immune systems are overloaded because the number of vaccines they receive has increased.

The Conversation· 12 Aug 2026

From erroneous + -ly.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level C1 · Advanced
Frequency Occasional
Updated