Moderate a beat, somehow (5)
I believe the answer is:
abate
'moderate' is the definition.
(I've seen this before)
'a beat somehow' is the wordplay.
'somehow' indicates anagramming the letters.
'beat' is an anagram of 'bate'.
'a'+'bate'='ABATE'
(Other definitions for abate that I've seen before include "drop off" , "Moderate" , "Ease off" , "retreat" , "Decline" .)