Guys without mike sing moving number and start to shake banners (7)
I believe the answer is:
ensigns
'banners' is the definition.
(I've seen this in another clue)
'guys without mike sing moving number' is the wordplay.
'guys' becomes 'men' (guy can mean a man).
'without' suggests deleting specific letters.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'moving' indicates an anagram (letters are moved around).
'number' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'men' with 'm' removed is 'en'.
'sing' with letters rearranged gives 'sign'.
'en'+'sign'+'s'='ENSIGNS'
'and start to shake' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ensigns that I've seen before include "Flag" , "Sensing (anag)" , "hauled up on deck?" , "officers? Of lower rank" , "US naval officers" .)