benefic

Benefic comes from Latin beneficus, which in turn comes from bene ("well") and facere ("to do"). The word was originally used by astrologers to refer to celestial bodies believed to have a favorable influence, and it's still used in astrological contexts. Benefic, beneficial, and beneficent are all synonyms, but there are shades of difference. Beneficial usually applies to things that promote well-being (as in "a beneficial dietary plan"), or that provide some benefit or advantage ("advice that proved financially beneficial"). Beneficent means doing or effecting good (as in "a beneficent influence"), but in particular it refers to the performance of acts of kindness or charity ("a beneficent organization"). Benefic, the rarest of the three, tends to be a bit high-flown, and it's mostly used to describe a favorable power or force.