굳히다

[구치다]

1. harden; make hard
To make a soft thing hard or stiff.

2. stiffen
To make one's facial expression, attitude, etc., gloomy or stiff.

3. strengthen; solidify
To make one's will, intention, resolution, etc., so strong that they do not change or shake.

4. solidify; strengthen
To not lose a good position or maintain advantageous circumstances.