A part of speech or speeches, persay: though throughout history injecting uh... into your speech, to buy time while your brain processed the upcoming verbal oratory, was thought to be a signal of the speakers inability to be "clear headed". In the future it will probably become perfecctly acceptable because of Barack Obama's repeated use of UH... Because of his popularity, UH...will be even more popular than "yaknowwhatimsayin" . It may now display a slow, thoughtful, deliberate train of thought.
UH...
when someone has sex and moans and makes sounds like uh uh uh
mike: i fucked Layla last night and she did the uh uh uh
Xavier: wow i wanna fuck her now! lets all have a three some and fuck each other
mike: great idea
A weak negation--no; not really; nope.
Not as strong as "nuh-uh".
Do you want to go to the concert?
Uh-uh.
The act of being mentally reduced to the state of only being able to say "Uh uh", usually induced by marijuana.
Guy 1: Damn, is that the basketball player John Wall over there?
Guy 2: Yeah, it sure is, but he's got the uh uhs.
Guy 1: He needs to lay off the weed!
Kid:Grandpa would you like some tea?
Grandpa: No thanks, Tea is liquid uh uhs.
Mum:Ok who wants salad?
Kid: Ew no, salad is uh uhs!