noun which may take the genitive case particle 'no'
extremely hard; rock solid; super stiff
Colloquial intensifier used for physical hardness, stiffness, or difficulty. Often used in casual speech or online contexts.
この問題は激硬で、なかなか解けない。
This problem is super hard and I just can't solve it.
激硬のステーキを噛み切るのに苦労した。
I struggled to chew through the rock-solid steak.