Nonbasic attack

A Nonbasic attack is a a specific type of attack -- they are usually more specialized types of attacks. The general rule is as follows

If it just mentions "attack" and not "basic attack", it's a nonbasic attack

Many special attacks, such as Stab, the attack from Manic, and the attack from Draketooth Rifle are nonbasic attacks. Note that many passive abilities do not trigger off of nonbasic attacks -- these effects specifically require basic attacks.