Bumptious \BUMP-shuh\ , adjective;
1. Crudely, presumptuously, or loudly self-assertive
This word is first attested in 1803 and is probably a humorous coinage based on the pattern of fractious, boisterous etc.
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Friday, March 25
Etymologies come from the Oxford English Dictionary and/or Etymonline.com