Agog is an adjective used to describe oneself as very enthusiastic or interested because of something or someone. It comes from French en gogues or in mirth.
A synonym for agog is agape.
Agape can be a noun, which comes from Greek, and literally means love. This noun form is sometimes used as part of a name (e.g., charities, businesses, churches).
Agape is more commonly used as an adjective or adverb to describe something as being spread open or wide apart. It may also mean in awe or thoroughly interested, as agog does. Most often it is used to mean both, that one’s mouth is agape or open in shock or awe.
Examples
The political world stood agog this week as Nigel Farage welcomed some “serious competition” for the South Thanet seat in the May general election. [The Independent]
The opening set of Italian music, which alternated between excerpts from Berio’s “Four Popular Songs” and two of Rossini’s many settings of the text “Mi lagnerò tacendo,” sounded alert but tonally washed out, and Bullock’s evocation of Baker through a string of six cabaret songs only approximated the vivacious charisma that kept the world of 1920s Paris agog. [SF Gate]
Roy got ahead early in overtime and left jaws agape at Bobcat Gym at the end of a 52-48 win over Sky View. [HJ News]
Instead, I read along with mouth slightly agape, marveling at this missive from a far-off place whose atmosphere, physical laws and inhabitants bear no resemblance to the ones I know. [Forbes]
Either you were agape in wonder or you wondered how you were lucky enough to know him. [Star Tribune]