What does the cryptic crossword clue "It’s rough to turn up with a blind trio (6)" mean?

The wordplay uses a reversal. PU (synonym="PU") + MICE (synonym="‘a blind trio’ – see how they run") = PUMICE The answer is PUMICE.

It’s rough to turn up with a blind trio (6)

Guardian Cryptic #29461 | 20 Down | 2024-08-14 flower