Portmanteau is a "real" word in English, and useful. Its older meaning of a large traveling bag is becoming obsolete (often used in literature before abt. 1920), but the newer meaning, for words like smog, is useful (a blending of two or more words - smoke and fog = smog). It also means a combination of things.
Pompitous has a nice sound to it. If we all decide on a meaning and use it regularly, soon it will become a real word (like proactive).