What does the cryptic crossword clue "Curve almost instant indication of circle? (6)" mean?

The wordplay uses a charade (building blocks). ARC (synonym="=curve, in geometry") + TIC (synonym="TIC") = ARCTIC The answer is ARCTIC.

Curve almost instant indication of circle? (6)

Independent Cryptic #11672 | 3 Down | 2024-03-08 flower