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1.
The state of a gentleman's penis when he is sexually excited almost to the point of spontaneous ejaculation.
Come on darlin', get yer kecks off, I'm rock hard!
by Richard Rockard June 22, 2006
 
2.
When a guy gets a erection.
Tyler got rock hard when his fuck buddy for the week started to rub his tip of his dick.
by vkfhdafhEWJ;FEWKJ January 16, 2008
 
3.
Intransitive verb. 1)The specific ability to perform adeptly a style of rock music which includes guitars, drums, and a blues influence. 2)To surpass all contenders in excellence, ability, or fame. 3) To render all viewers speechless at one's excellence, ability, or fame.
Music. "The vintage vinyl of Bad Company that my dad gave me rocks hard."
Excellence. "Congratulations on that summa cum laude! You really rock hard, Michelle!"
Ability. "Our band really rocked hard last night, didn't it?"
Fame. "The Beatles rocked hard."
by Rainwater September 28, 2007