What does the cryptic crossword clue "In adventure, Tom's unusually restrained (15)" mean?

The wordplay uses an anagram. anagram of IN + ADVENTURE, + TOM'S = UNDEMONSTRATIVE The answer is UNDEMONSTRATIVE.

In adventure, Tom's unusually restrained (15)

Daily Mail Cryptic #17320 | 2 Down | 2024-03-22 flower