harden
verb (used with object)
to make hard or harder.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
“I am hardening my resolve to seek more tasks for the sake of the people this year and make redoubled, devoted efforts to this end,” said Kim, grandson of the country’s founder, Kim Il Sung.
From Los Angeles Times ● Dec. 28, 2017