Nonplussed

[Oralee]

Often misused as meaning [unfazed], [but actually] means [bewildered].

[Renato]

(of a person) surprised and confused so much that they are unsure how to react.

[Couch Potatoe]

surprised, confused, and not certain how to react:

[Tanya Shivari]

([Verb]) [Unable] to act, [speak], or think; bewilderd

[Jessica]

[confused], [bewildered]

[Jason Yan]

Someone that doesnt have [a Google] Account, or perhaps any other [social network] account. A person who may have no knowledge of [social networks].

[Sommer]

When [someone] is [lickin] on a D

[Becky]

When your bank card wont work at another [banks] [ATM] because your bank is on the Plus System [debit] network, but the ATM is not.

[Donald Trump]

When you take the one [number] away from the other number. ( [No you didnt] pluss [em] you did the other thing)

[Magaret]

[Bemused]. This is the adjective derived from the verb nonplus.
[Oxford Dictionary]:
[nonplussed]: (of a person) surprised and confused so much that they are unsure how to react.
Part of speech: adj.