Within a month the rest fall and there's complete domination (7)
I believe the answer is:
mastery
'domination' is the definition.
(I know that domination can be written as mastery)
'within a month the rest fall' is the wordplay.
'within' means one lot of letters goes inside another.
'a month' becomes 'may' (May is an example).
'fall' is an anagram indicator (I've seen 'fallen' mean this).
'rest' is an anagram of 'ster'.
'may' enclosing 'ster' is 'MASTERY'.
'and there's complete' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for mastery that I've seen before include "in full command" , "dominion" , "Total control" , "Acquirement" , "Comprehensive knowledge (of a subject)" .)