ETYM French démonstratif, Latin demonstrativus.
1. Given to or marked by the open expression of emotion.
2. Serving to demonstrate; SYN. illustrative.
In grammar, of a pronoun, adjective, or determiner, pointing out or distinguishing (“I like this book; you can keep that”).

1. Intended to attract notice and impress others; SYN. pretentious.
2. Of a display that is tawdry or vulgar; SYN. pretentious, kitsch.