Having broken one's word about an early start, quarrelled (5)
I believe the answer is:
rowed
'quarrelled' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for rowed that I've seen before include "Maybe went from Putney to Mortlake" , "Oared" , "Propelled by oars" , "argued" , "Created a noisy squabble" .)