What does the cryptic crossword clue "Child artist, on the up, displaying sound technique (5)" mean?

The wordplay uses a reversal. SON (synonym="‘child’") + AR (synonym="AR") = SONAR The answer is SONAR.

Child artist, on the up, displaying sound technique (5)

Guardian Cryptic #29417 | 6 Down | 2024-06-24 flower