Drop dead of

[redgiant]

The caterpillars kept going in a circle in the pot. Eventually, after a week of circling around, they dropped dead of exhaustion and starvation with food only inches away from them.


Some books say in this sentence, "dead", as an adj, is used to describe "they", just like "He died a hero, he left a 20 year-old boy." But what is the meaning of "drop" here? Also, I don't understand why "of" is put in the sentence. Or Is " drop of " a idiom?

[jlinger]

Drop of is not an idiom.
Dropped dead means he died suddenly.

They dropped dead. Of what? Of exhaustion and starvation.

[BobK]

The caterpillars kept going in a circle in the pot. Eventually, after a week of circling around, they dropped dead of exhaustion and starvation with food only inches away from them.


Some books say in this sentence, "dead", as an adj, is used to describe "they", just like "He died a hero, he left a 20 year-old boy." But what is the meaning of "drop" here? Also, I don't understand why "of" is put in the sentence. Or Is " drop of " a idiom?

No it's not, but both 'drop dead' and 'dead of' are collocations. Why did they drop [=fall to the ground]? Because they died. What did they die of? The died of exhaustion.

b