What does the cryptic crossword clue "Excuse from officer not in line (3-3)" mean?

The wordplay uses a charade (building blocks). COP (synonym="police ‘officer’") + OUT (synonym="‘not in line’") = COPOUT The answer is COPOUT.

Excuse from officer not in line (3-3)

Guardian Cryptic #29454 | 19 Down | 2024-08-06 flower