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1.
Stupid
People are really dense.
by lilmissjessi July 17, 2003
 
2.
Someone who lacks common sense, acts like an idiot and makes a fool of themselves without realising.
I cant believe she cheated on him and didn't tell him for month, she thought everything would be okay, shes sooo dense.
by *Taylor_Kimi* January 12, 2006
 
3.
if used as a figurative (of a text), then dense means it's hard to understand because of a complexity of ideas...

if dense is used as figurative (of a person), then dense means that it's difficult to explain anything to that person because they can't make sense of complex ideas (because their head is too "dense" or "thick" to get anything through)

It does not mean stupid although it is often used to describe people who are also stupid. For example, a lawyer who argues what the word "is" means could be described as dense. Stupid is lacking in intelligence whereas dense infers that a person's head is too thick to teach anything to him/her.

People who exhaust you by asking for further clarification on anything from policies and procedures by asking questions they wouldn't ask had they understood your previous answer to one of their previous questions are dense - their skulls are too thick to get anything through to their heads so they don't understand even the simplest lowest common denominator definitions!

A dense person is the opposite of an airhead, although about as useful.
If you had to read this definition several times to understand it - and you still don't really understand it, it is because you are dense.
by unicornmoans April 23, 2010
 
4.
not exactly stupid, the person can be book smart but can also be: thick headed, clueless, lacking common sense, unable to catch onto hints
Caty: So has he catched on that you like him yet?

Helen: Sigh...no..Peter's so dense..
by nomnomnomcake:D November 19, 2011
 
5.
1. adj. slow, thick, dumb
2. n. a) a really slow person (who should most likely be hit on the head with a frying pan)
b) my friend Dennis who likes to type with his head flat on the table shouting I AM GOD!!!
Dense really should find a g/f before I throw him from the roof and set my (carniverous) rabbit on him.
by Spacey February 22, 2004
 
6.
Being very ignorant, and or difficult
You dense motherfucker
by DefaultProdigy June 23, 2014
 
7.
Whenever someone say's something retarded
Tim: How are you watching that song while reading that book?
Me: Obviously I'm listening to the song while reading the book.
Oh man it's getting really dense in here.
by LoOped October 02, 2011