It's an invented word. As to whether you should be bothered by it, you'd just have to judge from your friend's behavior and tone of voice. If your friend is affectionate but teases you sometimes, then it was probably affectionate teasing. The "-opolus" ending sounds like the ending of some dinosaur names, and reminds me of Big Bird's imaginary friend on Sesame Street, "Mr. Snuffleupagus." In English, when talking to children or close friends, it is not unusual to create diminutives or pet names on the spot by adding a few funny-sounding syllables at the end. I am guessing your friend is both complimenting you on being "spunky" (vivacious, spirited, assertive in a nice way) while at the same time not taking you too seriously (your being "spunky" is being seen as "cute" rather than truly assertive). For example, I talk too much. (I also write too much, have you noticed?) If I overdid it, someone might say to me "OK, Mr. Mouthatron" or "Listen to the Yackasaurus here" or "Well, aren't we the Chatterupagus today?"

P.S. I forgot to say that, whatever your friend meant by it, _if it "almost freaks you out,"_ if your friend uses it again, tell your friend. There's no right or wrong here, your feelings are your feelings. And if your friend _keeps using it_ after they know you don't want to be called it, then they are not acting like a good friend.

My first reaction is 'spunk'+(mon)opoly+ous'. Maybe he/she thought that you didn't consider carefully before you did something important or only had courage/全凭义气.

I am not aware of the context wherein the word was used. As always, if colloquialisms are used in English, or any other language, then situational and cultural factors come into play. The word "spunk" can also represent an informal "street word" used for semen/sperm and, as such, would be seen as rude and disrespectful. The adjective "spunky" is not used day-to-day English for the most part because of its association with the crude use of the word. Language evolves and changes; I would not use this word anymore.

My first reaction is 'spunk'+(mon)opoly+ous'.