Crossword Genius

Sad as Peter? (4)

Ross

I believe the answer is:

blue

I'm a little stuck... Click here to teach me more about this clue!

This might be a double definition.

'sad' is the first definition.
(similar in meaning)

'peter?' is the second definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.

'as' acts as a link.

Can you help me to learn more?

(Other definitions for blue that I've seen before include "in Oxford, it's dark" , "adult" , "Colour - smutty" , "This could be royal or navy" , "Dirty" .)

I've seen this clue in the Evening Standard.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.