English Reference
verb

obsess

v.
US /əbˈsɛs/ UK /ɒbsˈɛs/ ob·sess UK spelling obsesses, obsessing

  1. 01 B2 Upper Intermediate Informal

    to think or talk about something all the time because you are very interested in it.

    to be preoccupied with a single topic or emotion to a degree that excludes other thoughts. Often used intransitively with 'about' or 'over'.

    Simple

    He started to obsess about his weight after his doctor mentioned it.

    In context

    It is easy to obsess over minor details when you are under a lot of pressure to succeed.

    Usage

    Commonly followed by the prepositions 'about' or 'over'.

    fixatedwell
  2. 02 C1 Advanced Formal

    when a thought or worry stays in your mind and you cannot stop thinking about it.

    to preoccupy or dominate the thoughts of someone intensely. In this sense, the subject is the thought or idea, and the person is the object.

    Simple

    The fear of failing the exam began to obsess her every night.

    In context

    The possibility of a security breach began to obsess the lead engineer, leading to several sleepless nights of testing.

    Usage

    Used transitively; the thought or feeling is the subject.

    hauntpreoccupy

He's getting a divorce'." Alongside scenes where Guardiola obsesses over tactics, there are many where he gives candid speeches and berates his team.

BBC News· 17 Aug 2026

As we obsess over the tariff issue, the Americans are barely noticing.

Toronto Sun· 18 Aug 2026

From Latin obsessus, perfect passive participle of obsideō (“sit on or in, remain, besiege”), from ob (“before”) + sedeō (“I sit”); see sit, session, etc.; compare assess, possess.

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

This entry
Level C1 · Advanced
Frequency Occasional
Updated