Ties with loud assent anyhow (7)
I believe the answer is:
fastens
'ties' is the definition.
(I know this)
'with loud assent anyhow' is the wordplay.
'with' is a charade indicator (letters next to each other).
'loud' becomes 'f' (short for forte - 'loud' in music).
'anyhow' is an anagram indicator.
'assent' is an anagram of 'astens'.
'f'+'astens' is 'FASTENS'.
(Other definitions for fastens that I've seen before include "Bolts" , "Attaches firmly" , "fixes" , "Fatness (anag.)" .)