English Reference
adverb

mistakenly

adv.
US /mɪˈsteɪkənɫi/ UK /mɪstˈeɪkənli/ mis·tak·en·ly

  1. 01 B2 Upper Intermediate

    doing something because you believe something that is not true.

    in a manner based on a wrong judgment, belief, or misunderstanding.

    Simple

    I mistakenly thought the meeting was on Tuesday, so I missed it.

    In context

    The witness mistakenly identified the suspect based on a fleeting glimpse in the poorly lit alleyway.

    Usage

    usually placed before the verb it modifies or at the beginning of a clause.

  2. 02 B2 Upper Intermediate

    doing something by mistake without intending to do it.

    unintentionally or by accident; performing an action in error.

    Simple

    She mistakenly deleted the important file while cleaning up her desktop.

    In context

    The technician mistakenly disconnected the backup power supply during the routine maintenance check.

Usage mistakenly assume

On Thursday, Minns issued an apology and relayed news her body had been discovered after mistakenly announcing Hooper had been found alive.

The Guardian· 21 Aug 2026

Guardiola, by some, is mistakenly thought to be strictly married to a singular approach.

BBC News· 14 Aug 2026

From mistaken + -ly.

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

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated