a gleam in (your) eye

something that is thought about or planned but not yet started.

I remember when that invention was just a gleam in his eyes.

Etymology: based on the literal meaning of a gleam in your eye (= a sudden expression of an emotion in your eye)

• not in the least
• not in the same league
• not in the slightest
• not judge a book by its cover
• not know beans about
• not know beans about something
• not know from Adam
• not know if are coming or going
• not know if you are coming or going
• not know someone from Adam
• not know the first thing about
• not know the first thing about something
• not know the half of it
• not know the meaning of the word
• not know what hit
• not know what hit you
• not know where to put
• not know where to put yourself
• not know where to turn
• not know whether are coming or going
• not know whether to laugh or cry
• not know whether you are coming or going
• not know which way to turn
• not let the grass grow under feet
• not let the grass grow under your feet