In as simple or complex terms as you’d like. I have always described it as a “Deviation from the revolutionary line for purpose of capitalization, consolidation, or destruction of the Mass line in favor of the party bourgeois, landholders, etc” and a fundamental abandonment of scientific socialism in favor of pragmatic adoption of anti-socialist policy that does not lay the groundwork for communism.

There are, however, retreats back while remaining on the socialist road. In the USSR the NEP was used to maintain the socialist road after the civil war in a time of crisis (as opposed to the capitalist roading in the CCP on the back of steady economic, poltical and population growth during the GPCR), which still remains on the socialist road. The revolutionary line is still upheld and the contradictions of state are still resolved by a party of the proletariat.

Do you disagree? Have something to add? Let me know! Just remember to keep it civil and principled.