What does the cryptic crossword clue "Cross Siberia travelling with Communist League vans (9)" mean?

The definition is "Cross". The wordplay uses an anagram. anagram of SIBERIA CL = IRASCIBLE; definition: "Cross" The answer is IRASCIBLE.

Cross Siberia travelling with Communist League vans (9)

Guardian Cryptic #29568 | 3 Down | 2024-12-17 flower