According to dictionary means To bet on an uncertain outcome, as of a contest or To take a risk in the hope of gaining an advantage or a benefit or taking part in any activity or game where you risk money. 
The word "gambling" in the Quran's Arabic language is derived from a root word that literally means "easy," and "something attained with no effort." 
Gambling is mentioned in the Quran, alongside drinking alcohol as an abomination, a sin, and a grave harm to mankind. It was made clear that prosperity does not come through gambling. Gambling, among many other things, causes families to break, societies to suffer, and the economy to deteriorate, damaging the ethical foundation of any decent society.
O you who believe! Intoxicants, gambling, Al-Ansab, and Al-Azlam (arrows for seeking luck or decision) are an abomination of Shaitan's (Satan) handiwork. So avoid (strictly all) that (abomination) in order that you may be successful. Quran Surah Maidah 5:90
whoever says to his companions, 'Come let me gamble' with you, then he must give something in charity (as an expiation for such a sin)."Sahih al-Bukhari 6107 (Vol. 8, Book 73, Hadith 128) and Sahih al-Bukhari 6650 ( Vol. 8, Book 78, Hadith 645)
Buraida reported on the authority of his father that Allah's Apostle (ﷺ) said: He who played Nardashir (a game similar to backgammon) is like one who dyed his hand with the flesh and blood of swine. Sahih Muslim 2260 
Since the Arabs had been habituated to gambling for a long period of time, as was the case with alcohol, Allaah revealed His Commandments regarding its prohibition only gradually. In the Quran, the first verse regarding gambling is found in Soorah Al-Baqarah.
The meaning of that verse is: "They ask you about wine and gambling. Say, "In them is great sin and [yet, some] benefit for people. But their sin is greater than their benefit." And they ask you what they should spend. Say, "The excess [beyond needs]." Thus Allaah makes clear to you the ayath [of revelation] that you might give thought.” Quran Surah Baqrah 2:219
This verse did not clearly condemn and prohibit gambling. It was only said that sometimes the gambler gains money without any effort, but its moral evil is so great that a few material advantages are of no account. 
Secondly, gambling can cause mental health issues and physical health problems. According to a study conducted by Centre for Addiction and Mental Health (CAMH), mental health issues include stress, anxiety and depression which will actually cause a gambler to have more difficulty to sleep, think and solve problems. So, gamblers will tend to smoke more as well as to increase in alcohol consumption and possible drug usage to solve these problems. The study also shows severe problem gamblers will have a possible risk of self-harming behaviour such as suicide attempt. Pathological gamblers were more than twice as likely as people without gambling problems to have angina and nearly three times more likely to have liver disease. They were also almost twice as likely to suffer from tachycardia, an excessively rapid heartbeat (US Federal Survey on Psychiatric Disorders 2006).
Family and marital disturbances are a common end result of a seriously addicted gambler. Lorenz and Shuttleworth (1993) highlighted that fluctuation in mood states, lying and failure to meet obligation lead to marital friction and family disharmony. 
So grave is this problem, that it is diagnosed as clinical pathological gambling. It might be difficult to accept but people dealing with this addiction can suffer from depression, migraine, distress, intestinal disorders and other anxiety related problems.
The average compulsive gambler has debts exceeding $80,000.
There have been numerous news reports of corruption and fraud in state lotteries.
A student will skip classes; forget to study his lessons just because he is somewhere busy stacking cards or bidding online.
The most likely people who commit suicide are the ones prone to heavy alcohol, drugs or similar addiction.
Gambling problems lead to physical and emotional abuse of a partner or child. Researches show that 25-50% of spouses of compulsive gamblers have been abused.
It is true they follow the elders but when their ideals go berserk, it comes as a setback. They may lose their trust and start misbehaving, feeling down in the dumps.
Family members may avoid a gambler for he embarrasses them.
Gambling exists in much forms-racing, bingo, card games, dice games, lottery, slots and horse betting. Increased accessibility to internet has coined a new form of gambling-internet gambling. Youth are more likely to develop problems related to gambling than adults.
The stress related to these losses can hamper one’s health and ultimately one’s life.