keel over
[verb]
Synonyms: collapse, black out (informal), faint, pass out

[TahlilGaran] English Synonym Dictionary ▲

keel over phrasal verb (see also keel)
to fall over sideways:
Several soldiers keeled over in the hot sun.

[TahlilGaran] Dictionary of Contemporary English ▲

keel over
1.
to fall down suddenly because of illness or weakness.
Working outside in this heat, she was afraid someone would keel over.

2.
to die suddenly.
The old man simply keeled over on the sidewalk from a heart attack, I suppose.

Etymology: based on the idea of a boat that keels over (= turns over) with its keel (= bottom) up

[TahlilGaran] English Idioms Dictionary ▲

keel over
1. fall over and faint
Three of the members of the band keeled over because of the heat.

2. turn upside down, tip over
The boat keeled over in the middle of the lake but everybody was safe.

[TahlilGaran] English Idioms Dictionary ▲

keel over
v.
1. To turn upside down; tip over; overturn.
■ Usually refers to a boat.
The strong wind made the sailboat keel over and the passengers fell into the water.
2. informal To fall over in a faint; taint.
It was so hot during the assembly program that two girls who were standing on the stage keeled over.
When the principal told the girl her father died, she keeled right over.

[TahlilGaran] English Idioms Dictionary ▲