gobsmackedgob‧smacked /ˈɡɒbsmækt $ ˈɡɑːb-/ adjective British English spoken informal 
Examples
ExamplesEXAMPLES FROM OTHER DICTIONARIES
Thesaurus- "How did you feel when you heard that your wife was expecting triplets?" "Gobsmacked - absolutely gobsmacked."
THESAURUS► surprised
very surprised or shocked having the feeling you get when something happens that you did not expect: · I was surprised to see her again so soon.· I’m really surprised that he remembered my birthday.· Nobody was surprised when they split up.· a surprised expression
► amazed [not before noun] extremely surprised, especially by something good or by something that seems hard to believe: · I’m amazed that he survived.· You’ll be amazed when you see the difference.
► astonished extremely surprised: · He was astonished by how much she had changed.· an astonished look
► astounded extremely surprised or shocked. Astounded sounds a little more formal and a little stronger than astonished: · She was astounded by how much it cost.
► staggered/flabbergasted/dumbfounded [not before noun] extremely surprised or shocked: · ‘What?’ I said, utterly staggered by his answer.· She just sat there looking flabbergasted.
► stunned so surprised that you do not know what to do or say: · I was too stunned to protest.· Everyone seemed stunned by his outburst.· They listened in stunned silence.
► speechless so surprised that you cannot speak: · I was speechless when I heard that I’d won.
► taken aback [not before noun] surprised by what someone says or does, so that you are not sure how to react: · I was a little taken aback by her question.· Sharpe was somewhat taken aback by the girl 's directness.
► nonplussed formal surprised and a little confused: · She was nonplussed by such an odd question.
► gobsmacked [not before noun] British English informal extremely surprised – a very informal use: · I was absolutely gobsmacked when they told me I had passed.
Longman Language Activatorso shocked that you show it in your behaviour or appearance► speechless so shocked, angry, upset etc that you cannot speak: · The chairman was speechless when he heard that he had been dismissed.· Almost speechless, her mother managed to gasp out, 'And how long has this been going on?'leave somebody speechless: · Her children's behaviour is sometimes so bad that it leaves her speechless.speechless with rage/ horror/shock etc: · I didn't answer. I was speechless with rage.· The little girl seemed speechless with terror.I'm speechless spoken (=used to say how shocked or surprised you are): · Well, I'm speechless Anna. I really don't know what to say.
► stunned so shocked that you are unable to react immediately: · The news of his brother's death left him too stunned to speak.· Canada was completely stunned by the shooting, for it thinks of itself as a peaceful, gentle nation.· She looked pale and stunned -- it was clear that something awful had happened.stunned by: · His brother seemed stunned by the verdict.stunned silence (=when people stop talking, because something shocking has happened): · After a stunned silence, Peggy added, 'And I'm not going to change my mind.'
► dazed very shocked and unable to think clearly or do anything to improve the situation: · I stumbled from the office, feeling dazed and confused, and not really knowing where I was.· He stood there with a dazed expression on his face watching her pack her bags.dazed by: · Daphne is in hospital, still dazed by the events of the last ten days.
► gobsmacked British spoken so shocked that you cannot speak for a short time: · 'Do you feel surprised by your win?' 'Gobsmacked would be closer to the truth.'
so surprised that you cannot speak► speechless so surprised, by something very good or very bad, that you do not know what to say: · When I told him I was pregnant, he was totally speechless.· Brian's remark left his boss speechless with anger.
► be lost for words/be at a loss for words to feel so surprised and full of emotion that you are unable to speak: · She rang me and told me that Tom had died. For once in my life I was lost for words.· When I saw the devastation from our window in the morning, I was at a loss for words.
► dumbfounded/dumbstruck so surprised by something unexpected that has happened that you are confused and unable to speak: · I just remember feeling dumbstruck when I heard that John Lennon was dead.· Suddenly the stewardess started screaming while the passengers watched, dumbfounded.
► gobsmacked British informal so surprised that you cannot speak: · "How did you feel when you heard that your wife was expecting triplets?" "Gobsmacked - absolutely gobsmacked."