Come Together: wild tune grips one (5)
I believe the answer is:
unite
'come together' is the definition.
(I've seen this before)
'wild tune grips one' is the wordplay.
'wild' indicates anagramming the letters.
'grips' means one lot of letters goes inside another.
'one' becomes 'I' (Roman numeral).
'tune' is an anagram of 'unte'.
'unte' going around 'i' is 'UNITE'.
(Other definitions for unite that I've seen before include "pool resources" , "ally" , "Become an integrated whole" , "Amalgamate" , "Join together, become allies" .)