What does the term 'implacable' describe?

The term 'implacable' describes a state of being that is characterized by an inability to be satisfied or pacified. This means that a person or entity described as implacable is unwavering in their feelings, whether they be anger, resentment, or another strong emotion. For instance, if someone is implacable in their anger, they will not be swayed or calmed by attempts to reconcile or soothe them. This connotation highlights a level of intensity in emotions and a resistance to change, which aligns perfectly with the definition provided in the correct choice.

In contrast, the other options suggest a degree of leniency or acceptance that is contrary to the meaning of 'implacable.' Being casually accepting of defeat, maintaining a friendly demeanor, or being easily forgiving does not reflect the steadfastness implied by the term 'implacable.' In fact, these qualities indicate a level of flexibility or willingness to compromise that the concept of implacability directly opposes.