# keel over

idiom

Source: https://englishreference.com/idiom/keel-over
Updated: 2026-08-10

## Meaning

To collapse in a faint; to black out, to swoon.

## Examples

- She almost keeled over in the heat.
- He looks so pale that I think he will keel over.
- I often keel over when I see blood.
- The old man keeled over at the bus stop, and strangers rushed to help him.
- If you do not drink enough water while working in the garden, you might keel over from dehydration.
- The marathon runner crossed the finish line and suddenly keeled over because he was completely exhausted.
- The lead singer suddenly keeled over in the middle of the concert, leaving the audience shocked as the security guards rushed onto the stage.
- Overwhelmed by the news, she felt the room spin and keeled over into her mother's arms.

## Origin

The term originates from the nautical observation of a ship rolling so violently in the water that its keel, the central beam running the length of the hull from bow to stern, is exposed to the air. In maritime practice, the appearance of the keel indicates a vessel has capsized or is on the verge of doing so, a transition from the vertical to the horizontal that was later applied to the sudden collapse of individuals.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.