NET

4 Everyone who practices sin also practices lawlessness; indeed, sin is lawlessness.

Darby

4 Every one that practises sin practises also lawlessness^D9378; and sin is lawlessness.

Darby Bible Notes

lawlessness - To translate this 'sin is the transgression of the law,' as in A.V., is wrong, and gives a false definition of sin, for sin was in the world, and death as a consequence, before the giving of the law. see Rom. 5.13; 7.13. The Greek reads 'sin is lawlessness,' that is, the absence of the principle of law (not the law), or, in other words, of the control of God over the soul. I ought to have no will of my own, but be in obedience. The statement is reciprocal, and may be read 'lawlessness is sin.'

KJV

4 Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.