Last tested: Aug 18, 2017
To hide the title of an embedded look you can pass the show_title parameter in the url like so:
https://myinstance.looker.com/login/embed/%2Fembed%2Flooks%2F<lookid>%3Fshow_title%3Dfalse
This content is subject to limited support.
You have to pass a show_title query param in the embed domain URL.
Example:
<iframe id="looker" src="https://example.looker.com/embed/looks/3?embed_domain=http://localhost:3000&show_title=false"