General:
* Kindness
* Benevolence
* Magnanimity
* Liberality
* Altruism
* Philanthropy (specifically for charitable giving)
* Munificence (especially for lavish giving)
Focus on giving:
* Charity
* Giving
* Openhandedness
* Bounty
* Unselfishness
Focus on willingness to share:
* Sharing
* Unselfishness
* Selflessness
* Hospitality
More formal or literary:
* Munificence
* Largesse
* Bounteousness
The best synonym will depend on the specific context you are using it in.