know the first thing about

not know the first thing about something

to not know anything about a particular subject I don't know why you're asking Rob, he doesn't know the first thing about classical music.

Name	Pronounced	Usage
Sime	-	Macedonian
DÁIrÍNe	-	Irish
Tod	[tɔd]
Olympiodoros	-	Ancient Greek
Lala	-	Bulgarian
Rohit	-	Indian, Hindi, Marathi, Bengali, Odia, Gujarati, Kannada, Telugu, Nepali