Behold millions leaving fracas and moving (10)
I believe the answer is:
locomotion
'moving' is the definition.
(thesaurus)
'behold millions leaving fracas and' is the wordplay.
I cannot quite understand how this works, but
'behold' could be 'lo' (archaic exclamation meaning 'look!') and 'lo' is present in the answer.
'millions' could be 'm' (abbreviation) and 'm' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for locomotion that I've seen before include "Travelling" , "progress" , "It enables one to move" , "travel" , "Act of moving" .)