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1.
hfu
Means "Hey fuck you" in internet lingo.
Person 1: Excuse me but you suck.
Person 2: HFU
by Stan Greer December 28, 2006
 
2.
HFU
The HFU, or HAZARDOUS FOOD UNIT is a unit of measurement used to rate and compare foods, especially crappy foods.

* The lower the measure the better.
* Below 1 is OK
* Above 1 your body is taking a hit.
* Given the demonstrated creativity of 'food scientists' there is no upper bound.

Examples:

Orange => ~ 0.2 HFUs
Good chocolate (in moderation) => ~ 1.1 HFUs
Twinkie => ~ 20 HFUs
Dude, those pancakes covered with syrup and ice cream and cookies and that sprinkle shit and budwiser were the bomb but must have been 20 HFUs! I'm going home to chug pepto and die.
by mountaingeek August 10, 2010
 
3.
HFU
Harden the Fuck Up

Used to shut a whining pussy up. When you are at the end of your tether with them and don't want to listen to their sad ass stories anymore.
"I hurt my knee at soccer today"

"HFU, get over it."
by cat 3456 September 05, 2008