The adjective has 3 meanings:
Meaning #1:
filled with the emotional impact of overwhelming surprise or shock
Synonyms: amazed, astonied, astonished, astounded
Meaning #2:
knocked unconscious by a heavy blow
Synonyms: knocked out, kayoed, KO'd, out
Meaning #3:
in a state of mental numbness especially as resulting from shock
Synonyms: dazed, stupefied, stupid
