Nonsense; drivel; idle, meaningless talk.
"His story was nothing but blah that made no sense to anyone in the room."
In plain English: A blah is something that feels boring, uninteresting, and lacking any real energy or excitement.
"The party was boring and consisted mostly of blah after we ate too much food."
Usage: Use the noun blah to describe nonsensical or trivial conversation that lacks substance. As a verb, it refers specifically to the act of speaking in this dull and meaningless way.
To utter idle, meaningless talk.
"The meeting dissolved into nothing but blah as everyone repeated the same empty points without any real substance."
In plain English: To blah means to do something boring and pointless just because you have nothing better to do.
"The kids just sat there and blah-ed about their boring day all afternoon."
Dull; uninteresting; insipid.
"The movie was a total blah, leaving everyone bored by its dull and uninteresting plot."
In plain English: Blah describes something that is boring and uninteresting enough to make you want to say nothing about it.
"The movie was so blah that I couldn't even remember what happened in the end."
An expression of mild frustration.
"I can't find my keys and I just want to say blah about how annoying it is."
Sense "Idle, meaningless talk" (1940), probably imitative or echoic in origin. Compare Ancient Greek βαρ-βαρ (bar-bar, "unintelligible sounds") Adjective sense "bland, dull" (1919), perhaps influenced by French blasé ("bored, indifferent"). The blahs ("boredom, mild depression") first attested 1969; probably a blend of the blues + blah (adjective). Also may be connected with bleat