He's always moving and shaking to keep order (5)
I believe the answer is:
nomad
'he's always moving' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'and shaking to keep order' is the wordplay.
'shaking' is an anagram indicator.
'to keep' means one lot of letters goes inside another.
'order' becomes 'om' (Order of Merit).
'and' with letters rearranged gives 'nad'.
'nad' placed around 'om' is 'NOMAD'.
Can you help me to learn more?
(Other definitions for nomad that I've seen before include "someone who can't settle" , "wandering type" , "one of those with no fixed home" , "One travels from place to place with no permanent home" , "is one unsettled?" .)