The definition of love in Buddhism is: wanting others to be happy.
This love is unconditional and it requires a lot of courage and acceptance (including self-acceptance).
The "near enemy" of love, or a quality which appears similar, but is more an opposite is: conditional love (selfish love, see also the page on
attachment).
The opposite is wanting others to be unhappy:
anger, hatred.
A result which one needs to avoid is: attachment.
This definition means that 'love' in Buddhism refers to something quite different from the ordinary term of love which is usually about attachment, more or less successful relationships and sex; all of which are rarely without self-interest. Instead, in Buddhism it refers to de-tachment and the unselfish interest in others' welfare.
'Even offering three hundred bowls of food three times a day does not match the spiritual merit gained in one moment of love.'
Nagarjuna
"If there is love, there is hope that one may have real families, real brotherhood, real equanimity, real peace. If the love within your mind is lost and you see other beings as enemies, then no matter how much knowledge or education or material comfort you have, only suffering and confusion will ensue"
His Holiness the Dalai Lama from 'The little book of Buddhism'
Attachment and love are similar in that both of them draw us to the other person. But in fact, these two emotions are quite different. When we’re attached we’re drawn to someone because he or she meets our needs. In addition, there are lots of strings attached to our affection that we may or may not realize are there. For example, I “love” you because you make me feel good. I “love” you as long as you do things that I approve of. I “love” you because you’re mine. You’re my spouse or my child or my parent or my friend. With attachment, we go up and down like a yo-yo, depending on how the other person treats us. We obsess, “What do they think of me? Do they love me? Have I offended them? How can I become what they want me to be so that they love me even more?” It’s not very peaceful, is it? We’re definitely stirred up.
On the other hand, the love we’re generating on the Dharma path is unconditional. We simply want other to have happiness and the causes of happiness without any strings attached, without any expectations of what these people will do for us or how good they’ll make us feel.
http://www.viewonbuddhism.org/immeasurables_love_compassion_equanimity_rejoicing.html