The Buddha has been said to be compassion however i have not seen compassion described.
- What does it mean to be compassionate?
- How is it different to love, sympathy and empathy?
How is it different to love, sympathy and empathy
There's a description of compassion, empathy, and love in the Brahmavihara article on Wikipedia,
- Loving-kindness (Pāli: mettā, Sanskrit: maitrī) towards all: the hope that a person will be well; "the wish that all sentient beings, without any exception, be happy."
- Compassion (Pāli and Sanskrit: karuṇā): the hope that a person's sufferings will diminish; "the wish for all sentient beings to be free from suffering."
- Empathetic joy (Pāli and Sanskrit: muditā): joy in the accomplishments of a person—oneself or another; sympathetic joy; "the wholesome attitude of rejoicing in the happiness and virtues of all sentient beings."
What the word means in English
"Compassion" is from a Latin word, "co" meaning "with" and "pati/passio" meaning "suffer", so "compassion" means "suffer with".
If you're unable to help then it might mean literally suffering with: someone said of the earliest Christians that they'd love (have compassion for) each other; that if for example they didn't have enough food for two some day, then they would fast together and then eat together on the next day.
"Sympathy" is I think essentially just the same as "compassion", only it derives from Greek instead of Latin: "sym" means "with" and "pathos" means "feeling".
What the word means in Buddhism
Wikipedia's Karuṇā article seems like a fair introduction. It says,
The Pali commentaries distinguish between karuṇā and mettā in the following complementary manner: Karuna is the desire to remove harm and suffering (ahita-dukkha-apanaya-kāmatā) from others; while mettā is the desire to bring about the well-being and happiness (hita-sukha-upanaya-kāmatā) of others.
I guess that the Dhammapada includes one classic example, at the start of the chapter on Violence:
All tremble at violence; all fear death. Putting oneself in the place of another, one should not kill nor cause another to kill.