A Non-Aggression Pact or NAP is an agreement between alliances to not attack each other, typically with terms as to how to proceed in the event that a country from one alliance attacks a country from an other alliance.
An example of terms of a NAP are:
150% land:land on all hits.
72h retal window.
72h tag responsibility.
No FAing/assisting a tag that either tag is at war with.