What does the cryptic crossword clue "Clumsy human or amount of work one could do (3,4)" mean?

The wordplay uses an anagram. anagram of HUMAN + OR = MANHOUR The answer is MANHOUR.

Clumsy human or amount of work one could do (3,4)

Daily Mail Cryptic #17484 | 19 Down | 2024-11-07 flower