Crossword Genius

I left insect eating radish top roughly (5)

Ross

I believe the answer is:

circa

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

'roughly' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for circa that I've seen before include "Costa del Sol city" , "About (a time)" , "Preceding a date, this means about" , "Close to" , "Preposition meaning about, usually preceding a date" .)

I've seen this clue in the Sydney Morning Herald.
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.