What does the cryptic crossword clue "Nerds arise! Break the monotony (10)" mean?

The definition is "monotony". The wordplay uses an anagram. anagram of NERDS + ARISE! = DREARINESS; definition: "monotony" The answer is DREARINESS.

Nerds arise! Break the monotony (10)

Guardian Cryptic #26478 | 6 Down | 2015-01-26 flower