What are metta and karuna?

I'm wondering what these terms, *mettā* and *karuṇā* (loving-kindness and compassion), mean. - Are there suttas in which they're defined, otherwise where do the definitions come from? - Is there any important difference between these two terms, or do they mean the same thing? The words in the [metta chant](http://www.buddhanet.net/chant-metta.htm) are translated into English as being "free" from various forms of suffering. I think the Pali is just saying things like, "May I be with no-emnity" etc. Given [these definitions](https://en.wikipedia.org/wiki/Brahmavihara#Exegesis) , is "free from suffering" more a type of karuna rather than a type of metta, if so why is it in the "chant of metta"? Are they simply exact opposites, therefore the same thing? - In a translated phrase like "[May you be well](http://www.worldprayers.org/archive/prayers/celebrations/may_you_be_filled_with.html) " or "[May all beings be at ease](http://www.accesstoinsight.org/tipitaka/kn/snp/snp.1.08.amar.html) ", is that always the word [Sukha](https://en.wikipedia.org/wiki/Sukha) being translated? Or are there other adjectives (states of being) that are wished for? - How is metta (having desire for someone's well-being) compatible with equanimity? [These Dhamma Lists](http://www.insightmeditationcenter.org/books-articles/dhamma-lists/) warn that "indifference" is the "near enemy" of "equanimity"; but could you maybe explain briefly what the right view is, how to distinguish indifference from equanimity, or to make equanimity compatible with metta? > 1. Lovingkindness, good-will (*metta*): Near enemy – attachment; far enemy – hatred > 2. Compassion (*karuna*): Near enemy – pity; far enemy – cruelty > 3. Sympathetic joy, Appreciation (*mudita*), joy at the good fortune of others: Near enemy – comparison, hypocrisy, insincerity, joy for others but tinged with identification (my team, my child); far enemy – envy > 4. Equanimity (*upekkha*): Near enemy – indifference; far enemy – anxiety, greed - How is metta compatible with anatta and dukkha? Doesn't metta imply that there *are* people and that they *can* be happy, whereas anatta and dukkha being characteristic of all compound things kind of implies the opposite? - Do you agree with the following statement, [copied from here](https://buddhism.stackexchange.com/a/7275/254) : > People need Buddhism when their current raft has sunk. If there is food on the table, a comfortable place to sleep, and they have no complaints about their daily routine, then our jobs as Buddhists is to rejoice in their success (mudita). In summary, is metta necessarily a wish that other beings be enlightened, or could it mean something other than that?