When it comes to describing your significant other, there are various synonyms that can be used instead of "proper girlfriend". Some people might use "significant other" or simply "girlfriend" to refer to their partner. "Companion" or "partner" might also be good synonyms to use, as they imply a strong sense of closeness and shared experiences. Other possible synonyms include "beloved", "sweetheart", or "soul mate". Ultimately, the term you choose will depend on the context and the nature of your relationship with your significant other. Whether you use a traditional term like "girlfriend" or something more unique, it's important to express your love and appreciation for your partner in a meaningful way.