What does the cryptic crossword clue "Periodically, gantry behind sports ground may be so (5)" mean?

The wordplay uses a charade (building blocks). PE (synonym="‘sports’") + ATY (synonym="‘periodically g A n T r Y ‘") = PEATY The answer is PEATY.

Periodically, gantry behind sports ground may be so (5)

Guardian Cryptic #29445 | 12 Across | 2024-07-26 flower