What does the cryptic crossword clue "Enormous junk in attic (7)" mean?

The definition is "Enormous". The wordplay uses an anagram. anagram of IN + ATTIC = TITANIC; definition: "Enormous" The answer is Titanic.

Enormous junk in attic (7)

Telegraph Prize Cryptic #3037 | 22 Across | 2020-01-05 flower