Contra and Flip side

Contra noun - A member of the guerrilla force that opposed a left-wing government in Nicaragua.

Flip side and contra are semantically related. in opposite topic. In some cases you can use "Flip side" instead a noun "Contra", when it comes to topics like exact opposite.

Flip side noun - A different aspect of something (especially the opposite aspect).

Contra and flip side are semantically related. You can use "Contra" instead a noun phrase "Flip side".