blow up

Both

Sense-dependent: some meanings take an object and split, others take none. Check the sense you mean.

How to say it

Stress the particle, not the verb: blow UP. Saying “BLOW up” is the clearest learner tell — the verb stays light and the particle carries the beat.

A glide appears. Two vowels meet, so American English slips a /w/ between them: “blow up” → “blow-wup”. You do not insert it deliberately — it falls out of not stopping between the words.

4 meanings

  1. 1

    To explode, or to destroy something with an explosion.

    • The bomb blew up, causing massive destruction.
    • They blew up the old bridge before building the new one.

    Similar: explode, detonate

  2. 2

    To inflate something with air.

    • Can you blow up the balloons before the guests arrive?
    • It took twenty minutes to blow the air mattress up.

    Similar: inflate

  3. 3

    To lose your temper suddenly.

    informal
    • He blew up when he heard the project had been cancelled.
    • Don't blow up at her — she was only passing on the message.

    Similar: lose it, explode

  4. 4

    To enlarge a photograph or image.

    • Blow the picture up so we can read the sign in the background.

    Similar: enlarge

The particle logic

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More BLOW phrasal verbs

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blow up — meaning, examples & how to say it