出于

He gave the beggar a few coins out of pity.

They made donations to the people in the disaster areas entirely on a voluntary basis.

kill sb in self-defence

out of utmost sincerity

of one's own accord; on a voluntary basis; of one's own free will

from a sense of duty

out of/from ignorance

without intention

resign oneself to; out of sheer necessity; there being no alternative; only because one can do no better

for courtesy's/humanity's/charity's sake

out of curiosity/sympathy

be well-intentioned; out of kindness/good intentions; out of a good heart; with the best of intentions; mean well

actuated by ulterior motives

of one's own accord

with all one's heart; with one's whole heart