Adjective
With the mouth in an open position and the jaw hanging loosely, especially as indicating bewilderment or astonishment.
Synonyms: dazzled, dumbfounded, open-mouthed, stunned
(by extension) Unsophisticated or unthinking; dimwitted in appearance.
Synonyms: dopey, stupid, stupefied
(dated) Overly talkative; indiscreet.
Synonym: big-mouthed
"Bunch a slack-jawed faggots around here. This stuff [Red Man chewing tobacco] will make you a god-damned sexual tyrannosaurus -- just like me." (from Predator) Jesse Ventura
I'm useless when I meet writers I love - I go slack-jawed and stupid with awe. Katherine Boo
People are walking around Reykjavik with a mix of slack-jawed disbelief and complete delight: Imagine Edvard Munch’s wearing a party hat, and you’ve pretty much got the idea. Source: Internet
In the process, he realizes the daydreams of many who have sat slack-jawed in front of their TV sets, wishing harm on the entitled imbeciles who crave their 15 minutes, as well as the outlets that give them a forum. Source: Internet
"Yeah, but you're a slack-jawed yokel. Source: Internet
Bottle prices were fair and wines by the glass won't leave you slack-jawed. Source: Internet