Flag something wicked in light measure once (8,6)

I believe the answer is:

standard candle

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

'light measure once' is the definition.
I can't judge whether this defines the answer.

'flag something wicked' is the wordplay.
'flag' becomes 'standard' (standard is a kind of flag).
'something wicked' becomes 'candle' (I've seen this in another clue).
'standard'+'candle'='STANDARD CANDLE'

'in' acts as a link.

Can you help me to learn more?

I've seen this clue in The Times.

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.