Appreciation is the quality of recognizing and valuing something, while unappreciation is the lack of appreciation. Antonyms for unappreciation would be words and phrases that express the opposite of it, such as appreciation, esteem, gratitude, respect, recognition, admiration, and thankfulness. These words denote a positive attitude towards someone or something, indicating that they are cherished, respected, or admired. Appreciation acknowledges the efforts of others, which can lift morale and strengthen relationships. In any situation, it is important to show appreciation and avoid unappreciation, as it can lead to dissatisfaction, resentment or negativity.