härten

To harden (literally)

To make something harder or more rigid, often through a physical process. This can refer to materials like metals, plastics, or even muscles.
- Example: Der Schmied härtete den Stahl, indem er ihn erhitzte und dann schnell in kaltes Wasser tauchte. (The blacksmith hardened the steel by heating it and then quickly plunging it into cold water.)

To temper (literally)

To treat a material, typically steel, to improve its hardness and strength. This often involves heating and cooling the material in a controlled manner.
- Example: Die Klinge des Schwertes wurde sorgfältig gehärtet, um ihre Schärfe und Festigkeit zu verbessern. (The blade of the sword was carefully tempered to improve its sharpness and strength.)

To toughen (figuratively)

To make someone or something stronger, more resilient, or less susceptible to harm or difficulty. This can refer to both physical and mental toughness.
- Example: Die Soldaten wurden durch das harte Training gestählt. (The soldiers were toughened by the harsh training.)

To become hardened (figuratively)

To develop a callous or insensitive attitude, often as a result of difficult experiences. This can be a negative connotation, suggesting a loss of empathy or compassion.
- Example: Durch die jahrelange Gewalt wurde ihr Herz gehärtet. (Her heart was hardened by years of violence.)

Grammatical Usage

Sich härten is a reflexive verb, meaning the action is directed back onto the subject. In English, it is often translated as “to harden oneself” or “to become hardened.”
- Example: Er härtete sich gegen die Kälte ab, indem er jeden Morgen kalt duschte. (He hardened himself against the cold by taking cold showers every morning.)
Härten can also be used as a transitive verb, meaning the action is directed towards an object. In this case, it is typically translated as “to harden” or “to temper.”
- Example: Der Schmied härtete die Klinge des Schwertes. (The blacksmith hardened the blade of the sword.)