affectation + -ous or + -ious.
affectatious (comparative more affectatious, superlative most affectatious)
- Pretentious, artificial, fake, sham, feigned; doing something just for show.
2004, “Chapter Two”, in The Hidden Handshake: National Identity and Europe in the Post-Communist World (Political Science), Rowman & Littlefield, →ISBN, page 54:
At the same time, American intellectual and artistic elites, … help create a sophisticated, if sometimes affectatious urban mentality.