blah

Nonsense; drivel; idle, meaningless talk.

A general or ambiguous feeling of discomfort, dissatisfaction, uneasiness, boredom, mild depression, etc.

A fool, an idiot.

Dull; uninteresting; insipid.

Well, the new restaurant seems nice, but their menu is a little blah.

He was struck by how much pleasure they seemed to take in their daytime lives, how blah their night work was by contrast, how altogether meaningless; […]

Low in spirit or health; down.

I decided to go exercise rather than sit around all day feeling blah.

An expression of mild frustration.

Blah! Why can't I get this computer to work!

Imitative of idle, meaningless talk; used sometimes in a slightly derogatory manner to mock or downplay another's words, or to show disinterest in a diatribe, rant, instructions, unsolicited advice, parenting, etc. Also used when recalling

Yeah, yeah, blah blah blah, Mom, you said this all yesterday.

And then he was like, "Oh, my brother's an Internet millionaire, blah blah blah." Like I care!

Representing the sound of vomiting.