What does the cryptic crossword clue "Dash, it’s rough being an ambitious type! (9)" mean?

The wordplay uses an anagram. CAREER (synonym="‘dash’") + IST (synonym="IST") = CAREERIST The answer is CAREERIST.

Dash, it’s rough being an ambitious type! (9)

Guardian Cryptic #29424 | 25 Across | 2024-07-02 flower