こいつは困ったぞ。

[mike-lima]

English Translation

Here’s a fine how-do-you-do.

I think “This guy is really annoying.” is the literal sense of the sentence.I wasn’t aware of the English idiom until now…

[MsFixer]

@mike-lima
The Japanese sentence doesn’t mean “this guy is really annoying.” We say this phrase when we are under a troublesome situation. But the situation isn’t likely to be caused by a guy. For example, you accidentally lost your smartphone and wallet, and you would say こいつは困ったぞ. Please note that the Japanese sentence is usually spoken only by male.

If you mean “this guy is really annoying,” the Japanese sentence is:

こいつは厄介者だ。(pron, やっかいもの)
こいつ、マジでウザい。