rock hard

adjective4

1. •
   As tough, hard, or inflexible as a piece of rock.

   • One of humankind's oldest maladies, kidney stones are rock-hard — 1998
2. •
   With muscles developed and toned to a high degree, especially the muscles of the abdomen.

   • He was pale but rock-hard from exercise, and still had a grunt's haircut. — 2007
3. •
   (informal) Having a very fully erect and stiff penis

   • Tommy Lee first shivered when he felt the tongue in his ear, but his whole body shuddered when he felt the deputy's rock hard cock press along the length of his ass crack. — 2008
4. •
   (figurative) With strongly held beliefs and opinions, deep conviction.

   • Mark does not seem to be suffering from any inner conflict, in that he is rock hard and will not budge from this position. — 2010