Sadaqah
or  ( , "charity", "benevolence", plural  ) in the modern Islamic context has come to signify "voluntary charity". According to the Quran, the word means a voluntary offering, whose amount is at the will of the benefactor. Etymology and meaning
 literally means "righteousness" and refers to the voluntary giving of alms or charity. In Islamic terminology,  has been defined as an act of "giving something... without seeking a substitute in return and with the intention of pleasing Allah." Meanwhile, according to Ar-Rageeb al-Asfahaani “Sadaqa is what the person gives from what he possesses, like , hoping to get closer to Allah." The term  stems from the Arabic root word  (s-d-q, ), which means "sincerity";  is considered a sign of sincere faith. The three-letter root of this word, s-d-q, also means, "to speak the truth", "to be sincere", and "to fulfill one's promise". All of these aspects of honorable behavior indicate the links between generosity and a healthy society. Some modern researchers also etymologically link the word  to the Hebrew   (almsgiving). Some experts hence conclude that  is a loanword. Examples of  include:
 to administer justice between two people
 to remove harm from a road/removing thorns, bones and stones from paths
 to speak a good word
 to take a step towards prayer
 to guide the blind
 to support the weak with the strength of your arms
 to smile at others

In Islamic texts

Quran

The word  (meaning the obligatory ) occurs 30 times in the Quran—27 times linked with prayer, three times not so-linked. The word  (non-obligatory charity) and its plural () occur 13 times in the Qur'an.

"" is used in the Quran to cover all kinds of charity. has been called  because it is also a kind of compulsory charity. It is an obligatory  while ordinary  are voluntary. Thus,  has to be collected by the  (collector) or the government (the Islamic state) as a compulsory levy. According to the Quran,  leads to the purification of the benefactor. The Quran says that  does not need to be in a material form and can also be a "voluntary effort", or a kind word. This is in agreement with a narration attributed to Muhammad which says "every good deed is a form of ." Kind words and "compassion" are better than  accompanied by "insult", from the viewpoint of the Quran, and it is better for the donations to be offered "discreetly" to those in need rather than doing it in public in order to be acknowledged by them. The Quran also criticizes donating aimed at appearing generous, or compromising the value of  by "ostentatious public behavior" done just to "render a normally charitable act purely self-serving." The Quran suggests that  is not meant only to support the poor, but also can be donated to others who "were not visibly in need" and also who either needed assistance to enhance their life or required to be directed towards new jobs and "economic opportunities". Among the many verses on , either voluntary or obligatory, are these: 
And be steadfast in prayer; practise regular charity; and bow down your heads with those who bow down (in worship). They ask thee what they should spend (In charity). Say: Whatever ye spend that is good, is for parents and kindred and orphans and those in want and for wayfarers. And whatever ye do that is good, Allah knoweth it well. Kind words and the covering of faults are better than charity followed by injury. Allah is free of all wants, and He is Most-Forbearing. Allah will deprive usury of all blessing, but will give increase for deeds of charity: For He loveth not creatures ungrateful and wicked. Those who believe, and do deeds of righteousness, and establish regular prayers and regular charity, will have their reward with their Lord: on them shall be no fear, nor shall they grieve. So fear Allah as much as ye can; listen and obey and spend in charity for the benefit of your own soul and those saved from the covetousness of their own souls, they are the ones that achieve prosperity. Hadith
According to some , "a kind word and smile" can be considered as  and the best form of it is "passing on knowledge." Also, Muhammad said in a  that  removes seventy gates of evil. Difference from 

The word  is interchangeably used with  and  in some contexts, but while  is obligatory,  usually refers to voluntary donations. is a required minimum contribution by Muslims in terms of money and property or goods that can help Muslims who need assistance, while  can be in the form of money, deeds, property, or salutations. The term  was used in the Quran and Sunnah for both  and charity. Among the differences between them is that in the case of , the amount is fixed, utilized according to that which has been stated by the Islamic Law, and paid only once a year. However charity has no fixed percentage and one is free to pay it as many times as one can afford or feel inclined to it. Etiquette

 should come from one's legitimate possessions and property. It is better to offer  in secret. should not be accompanied by reproaching the person who is given the . should be out of pure intentions for God. Sadaqah should be from possessions you love. Categories of the entitled
According to , there are eight categories of people who are entitled to receive  (). They are: 
The poor (), that is low-income. The needy people (). The officials appointed to receive  ( administrators). Those whose hearts have been (recently) reconciled to Islam (). To free the slaves and captives. Those who are overburdened with debt. In the cause of Allah to spread the message of Islam. To those who are wayfarers (travelers who do not have enough money to go back home). Significance

Social contribution
 It enhances the well-being of the people in Islamic society. It helps in fulfilling the requirement of the poor Muslims. It lightens the debt of the Muslim debtors. It helps in taking care of those whose hearts have been (recently)reconciled (to the Truth). It helps the stranded Muslims to complete their journey. It helps in the healing of various Sickness (according to the prophet of Islam). Spiritual effects
 It purifies human's heart from the sins of malice, greed, and the obsessive love of wealth. It increases the wealth. It removes bad luck. It helps in crossing the bridge of Siraat. It guarantees heaven. See also

Al-Kaffarah
Alms
Khums
Tzedakah
Zakat
Zidqa, almsgiving in Mandaeism

Notes

 in Literary Arabic: , the first and the last vowels could be backed to  and the last vowel could be turned to . The second vowel could also be backed to  or fronted to . Thus . See Arabic phonology. References

Further reading
 
 Urdu Book about Islamic concept of Sadaqah مالی قربانی کا اسلامی تصور

Alms in Islam
Arabic words and phrases
Islamic terminology
Islamic worship