The hardening of an idea into a plan for a novel is a vague process and hard to describe.
Political preferences are hardening; folks in a given district are consistently voting the party, not the candidate.
Liam describes his life “drying up and hardening, like one of those mouse carcasses you find beneath a radiator.”
Nor can the hardening of positions in Israel can be attributed to Israeli insecurity.
“The sensation was one of hardening of the organs,” he chuckled in the retelling.
For sin weakens the sense of individual guilt, and thus deceives men by hardening their hearts.
They were street boys; their lives had been spent in a hardening atmosphere.
That very night a sharp frost set in, hardening the moist and swampy grounds over which they had to pass.
He was hardening his throat, and so slept with a wet towel about it.
Their long rest had rendered them somewhat “soft,” though the hardening would be rapid.