English Reference
adverb

aback

adv.
US /əˈbæk/ UK /ɐbˈæk/ aback

  1. 01 B2 Upper Intermediate

    surprised or shocked by something unexpected.

    startled or disconcerted by a sudden development; almost exclusively used in the passive construction 'to be taken aback'.

    Simple

    I was taken aback by how much the city had changed since my last visit.

    In context

    The CEO was visibly taken aback by the shareholders' blunt refusal to approve the proposed merger during the annual meeting.

    Teacher's tip

    Learners should treat 'taken aback' as a single lexical unit rather than trying to use 'aback' on its own.

    unmovedprepared
  2. 02 C2 Proficiency Technical Science

    when the wind blows against the front of a ship's sails, pushing them back against the mast.

    the state of a ship's square sails when pressed against the mast by a headwind. Used as a predicative adverb.

    Simple

    The ship was caught aback by a sudden change in the wind's direction.

    In context

    The vessel was laid aback to reduce its headway, allowing the crew to safely lower the lifeboats into the swelling sea.

    Teacher's tip

    This is the original nautical source of the common idiom; it is rarely encountered outside of maritime history or technical sailing manuals.

Usage

Almost always follows the verb 'to be' and the past participle 'taken'.

Pitfall
The news took me aback.I was taken aback by the news.

While 'take someone aback' is grammatically possible, the passive form 'be taken aback' is the standard idiomatic usage.

The thing is, usually we cannot because we’ve got to work, we have kids, we’ve got to run, and so we’re taken aback by the changing needs of older people.

The Guardian· 4 Sept 2026

Etymology 1

From Middle English abak, from Old English onbæc, equivalent to a- (“towards”) + back. Compare West Frisian tebek (“aback”, adverb, literally “to/at back”), Swedish tillbaka (idem.).

Etymology 2

From Latin abacus.

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

This entry
Origin Old English onbæc
Level B2 · Upper Intermediate
Frequency Occasional
Updated