Infaq(إنفاق) is an Arabic word meaning charity simply to please God without asking for any favor or hoping for a return. The word yunfiqoon has been used often in the Quran as a trait of a good Muslim. It is different from Zakat, which is obligatory on Muslims, or Sadaqah, which is charity for obtaining specific return or protection from some adverse event.
^وَمِمَّا رَزَقْنَاهُمْ يُنفِقُونَ ﴿٣﴾ Al-Quran, Sura Baqra Ayah 3
^Al-Quran: Surah Al-Baqra : O YOU who have attained to faith! Spend [in Our way] out of what We have granted you as sustenance ere there come a Day when there will be no bargaining, and no friendship, and no intercession. And they who deny the truth -it is they who are evildoers! (254)