When someone starts talking about something they don't have a clue about and start making it up as they go.
Or
Someone who messes up Bad or mistakes something or someone for something or someone else
OMG Megan had no idea what she was talking about in science. She was having such an Elise moment.
A name given to a girl who is breathtakingly beautiful both inside and out. She is wise beyond her years. Sexy donning both a fat ass and small waist and she genuinely is good company to be around. She is simply unmatched.