My favorite short description of Humanism.
"Humanism is a rational philosophy informed by science inspired by art and motivated by compassion. Free of theism and other supernatural beliefs, Humanists reside in the natural world and thus derived the goals of life from human need and interest rather than from theological or ideological abstractions and asserts that humanity must take responsibility for it's own destiny." Definition inspired from Corliss Lamont.
I wrote down a definition of Humanism a few years ago and will share it, too. It is from Jim Al-Khalili, theoretical physicist and leadership member of the British Humanist Association: "Reason, decency, tolerance, empathy and hope are human traits that we should aspire to, not because we seek reward of eternal life or because we fear the punishment of a supernatural being, but because they define our humanity." I would add that we do have to think about our destiny as intertwined with the other life forms that reside on this planet. We reside in the natural world, yes, so that means we humans have a responsibility to clean up the messes we have made when they affect the health of the planet.
I find it odd to deny ideological abstractions when you are trying reduce a complex belief system down to a short paragraph. It in itself seems to be teetering on the edge of the ideological. I think in the same way that every Christians view of Christianity is different, it is the seem followers of Humanism, they will all have a different way of defining it. Not that you need to get rid of the descriptions all together, but you either need to define only your own understanding of the term, or if you want to create universal description, it needs to be a more vague.
Many atheists now sailing under the flag of „humanism“ do not realize that "humanism" is only the continuation of Christianity by other means. Since Feuerbach and Freud we know that the gods are merely projections of the human mind, and that we worship ourselves in the image of "gods".
Durkheim applied this to society: In the form of religions, the collectives, the societies celebrate themselves and thus secure their cohesion.
The humanist ideology renounces all this traditional religious hullabaloo; it does not take the detour via the gods, but here humans worship themselves unabashedly by inventing a special "dignity" that sets us apart from the rest of nature. This „dignity“ is nowhere to be found in nature, it is a fiction, just like Zeus or Vishnu are fictions. Atheists are ready to acknowledge that these gods are figments of imagination, but they fail to realize that the same holds true for the intellectual core of humanism.