Tax evasion or evasion of tax can be defined as the act or an attempt to avoid tax payment. This act or attempt generally involves the use of fraudulent means, and is intentional.
Tax evasion is entirely different to the late payment of tax or making use of legal errors or loopholes when trying to minimize the tax amount.
If an entity tries to escape the tax payment partially, involving fraudulent means, it would still be considered tax evasion.
Evasion of tax, once proven, is a punishable, federal crime. Tax evaders usually try to hide their financial assets from the authorities with an aim to lower their taxable income or assets.