A state of great surprise or shock; the feeling of being amazed by something unexpected.
From astound plus the suffix -ment (which creates nouns from verbs, meaning the result or state of an action), forming a noun for the emotional state of being astounded.
While 'astonishment' is the common word, 'astoundment' shows English has multiple ways to name the same emotion—different synonyms often reveal different historical layers in how a language develops.
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