From both a literal point of view and a Sharʿī point of view?
Purity - Ṭahārah
“Success is Surely achieved by him who purifies himself”
The reason why Zakāt has been called Zakāt, is because it purifies the person who discharges it from the baseness of sin and miserliness.
Allāh says in Sūrah At-Taubah
“Take Ṣadaqah (obligatory alms) out of their wealth through which you may cleanse and purify them”
Another meaning is Increase - NumūꜤ. The reason why it is called ‘increase’ is because Zakāt is a means for a person’s wealth to grow. Allāh gives a return to the person who discharges their Zakāt in this world and gives them reward in the hereafter.
Another meaning is truthfulness. And the reason is when a person discharges Zakāt, it shows their truthfulness in their faith and the state of their heart. The truthfulness and purity are a mark of their sincere intention
When a person gives Zakāt, then this becomes a form of them purifying their wealth. And once our wealth has become purified, Allāh gives us barakah, blessings in our wealth and this in turn causes it to increase. Subḥānallāh. So, a person will give the Zakāt and Allāh will give them barakah, blessings.
One thing we must remember here is that it is not about the amount of money we have, but the amount of barakah Allāh puts in our money. We could have one person who has a lot of money, spends £150 a week shopping and even before the week is over, all the food has run out. On the other hand, a person goes and spends £50 and after a week, there is still food left, so you can see how Allāh can put barakah in a person’s wealth.
So, what is the SharꜤī meaning, the Islamic meaning?
The meaning is “the transfer of ownership of a certain amount of wealth that has been prescribed by the law from a rich person to a poor Muslim who is not a Ḥashimī and neither a slave of a Ḥashimī for the sake of Allāh ”.
What does this mean? A person who is classified in Islām as eligible to give Zakāt, has to transfer ownership of wealth to a person who is classified in Islām as being eligible to receive Zakāt. This person cannot be from the family of Rasūlullāh or be a freed slave from his family. More details on this later. The recipient must also be a Muslim and must then be able to do with the wealth whatever he or she wishes.
So, if a person had a room to rent in his house and he has a poor tenant. He says to his poor tenant that you can live here free for the next year, and the amount of rent equals how much Zakāt they need to pay. This will not satisfy the criteria of ownership so the persons Zakāt will not be discharged.