Crossword Genius

Diminishes a beast, somehow (6)

Ross

I believe the answer is:

abates

Here is my best explanation:

'diminishes' is the definition.
(abating is a kind of diminishing)

'a beast somehow' is the wordplay.
'somehow' indicates an anagram.
'beast' anagrammed gives 'bates'.
'a'+'bates'='ABATES'

This clue was last seen in Mirror