altruist:
(plural: ‘altruists‘)
a true altruist, Conor Grennan, USA
a person (or animal) who is good to others, even making personal sacrifices, by nature and without expecting anything in return; a selfless person;
a person who is selfless and always thinks of the welfare of others or the society, making money donations, participating in social work, etc., even at the risk of losing his/her comforts or own life, without expecting anything in return; a philanthropist,

Mrs Rahim is a true altruist who has spent much of her wealth and time for the benefit of those in need, and for the welfare of the society in general, though those people are not her relatives or friends.
An altruist is a selfless person who does anything to help others, with altruistic intentions basing on the principle of altruism.
An excerpt citing an example of ‘altruism‘ from
Austin Cline, About.com Guide to Atheism since 1998
“The ant in question, a Brazilian species named Forelius pusillus, buries the entrance to the colony every night. To ensure that the entrance is completely hidden, a few ants remain outside to finish the job — and those ants die before the colony comes back out the next morning.
‘These findings, which will appear in the November issue of the journal American Naturalist, show that staying outside was suicidal. “In a colony with many thousands of workers, losing a few workers each evening to improve nest defense would be favored by natural selection,” said co-author Francis Ratnieks, an insect biologist at the University of Sussex, U.K. …’ “
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Another example from
http://www.cbc.ca/health/story/2006/0 /02/altruism060302.htmlInfants show early signs of altruism
As part of the study, Warneken developed scenarios in which an adult needed help. In one case, he dropped a clothespin on the floor while hanging up laundry.In 84 per cent of cases, infants as young as 18 months, who were not familiar with Warneken, would help retrieve the peg.During the test, he never asked for help. He also did not thank or reward the child, since the study was designed to show if the toddlers could show altruistic behaviour.
When he deliberately threw a peg on the ground, the infants didn’t help to retrieve it. That suggests the babies were able to infer when the peg was needed to complete the task of hanging up clothes.”
