Sesquipedalian
Part of speech: noun
Definition: A person who uses long words. A long word.
Part of speech: adjective
Definition: long; polysyllabic. Pertaining to or given to the use of overly long words.
Pretentious
Part of speech: adjective
Definition: Marked by an unwarranted claim to importance or distinctionOstentatious; intended to impress others
Example sentence: I never want to be pretentious.