A targeted attempt to steal sensitive information such as account credentials or financial information from a specific victim, often for malicious reasons.
So what is the difference between phishing and spear phishing?
Phishing and spear phishing are very common forms of email attack designed to performing a specific action—typically, clicking on a malicious link or attachment. The difference between them is primarily a matter of targeting. While phishing targets a large number of people at once, spear phishing emails are carefully designed to get a single recipient to respond.
Spear phishing is targeted at specific individuals within an organization. It is this specific characteristic that makes spear phishing attacks have such a high success rate. Spear phishing attackers do enough research on their target before attempting a campaign to guarantee higher success of attack.