What is the difference between 当惑する , 戸惑う, はっとする and 度肝を抜く I get that all 3 kind of express the same idea of "being taken aback" or taking someone aback, being shocked, bewildered, surprized. I am wondering what are their subtle differences in nuance (if any) and if all can be used in similar scenarios or have to abide by certain restrictions. For example I've seen being used only in causative form when we want to say "I was shocked" -> ""

**** (noun + verb)
_common word_

Originally is a noun which means "bewilderment", it can be used as a verb when connecting or just as a noun (its main function).

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**** (verb)
_common word_

It is a verb in itself for "to be confused", "to be bewildered".

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**** (adverb + )
_common, narrative_

is onomatopoeic. You can use it as part of a speech but you will likely see it in storytelling as it supports monologues of actions.
it expresses the swiftness of a surprise and can be used before different verbs. For instance :


I [with a surprise] lost my breath at the sight.

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**** (noun + verb, expression)
_not common, narrative_

"to be stunned"
More of an expression, its use is more likely to be seen in literature.