Penetration refers to the act of piercing or entering into something. There are various synonyms for penetration that can be used to indicate the same meaning. Some of the common synonyms for the word penetration are infiltration, perforation, puncture, entry, invasion, incursion, and interpenetration. These words can express the idea of penetration in different contexts. For instance, infiltration can refer to the gradual seeping of something into another substance or structure, while perforation or puncture can denote the creation of a hole or opening by piercing through a surface. Overall, by using synonyms for penetration, writers can add more variety and precision to their language.