Expresses that something happens or is the case for an unclear or unspecified reason. Often used when the speaker cannot pinpoint the cause.
For some reason I don't feel well today.
Somehow I feel I can't trust what he says.
whatsitsname; what-you-call-it; Mr. so-and-so
Used as a placeholder when the speaker cannot recall or does not want to specify a name or term. Often appears in the pattern ～とか何とやら.
That, what's-his-name, was here again.
He seems busy with a new project or what-you-call-it.
Follows a noun or phrase to imply there are other similar things left unmentioned. Similar to など, but more colloquial and often used when the speaker is being vague.
He's always complaining about his work, his salary, and so on.
Lately, with health and all that, I started going to the gym.