General Antonyms:
* Compassionate: This is a common and direct antonym, implying empathy and concern for others.
* Kind: This suggests gentleness and a desire to do good.
* Merciful: This implies showing forgiveness and leniency.
* Sympathetic: This indicates understanding and sharing the feelings of others.
* Caring: This refers to showing concern and affection.
* Warm: This evokes a feeling of friendliness and emotional connection.
More specific antonyms:
* Tender-hearted: This suggests sensitivity and vulnerability.
* Big-hearted: This emphasizes generosity and willingness to help.
* Humanitarian: This emphasizes concern for the welfare of others.
* Benevolent: This indicates kindness and a desire to do good.
The best antonym will depend on the specific context and the nuance you want to convey.